Showing papers in "Functional & Integrative Genomics in 2008"
TL;DR: Test the hypothesis that the dehydrin (Dhn) multigene family can serve as an indicator of the entire transcriptome response and investigate the response of barley cv.
Abstract: Low temperature and drought have major influences on plant growth and productivity To identify barley genes involved in responses to these stresses and to specifically test the hypothesis that the dehydrin (Dhn) multigene family can serve as an indicator of the entire transcriptome response, we investigated the response of barley cv Morex to: (1) gradual drought over 21 days and (2) low temperature including chilling, freeze-thaw cycles, and deacclimation over 33 days We found 4,153 genes that responded to at least one component of these two stress regimes, about one fourth of all genes called "present" under any condition About 44% (1,822 of 4,153) responded specifically to drought, whereas only 38% (158 of 4,153) were chilling specific and 28% (119 of 4,153) freeze-thaw specific, with 341% responsive to freeze-thaw and drought The intersection between chilling and drought (319%) was somewhat smaller than the intersection between freeze-thaw and drought, implying an element of osmotic stress response to freeze-thaw About 824% of the responsive genes were similar to Arabidopsis genes The expression of 13 barley Dhn genes mirrored the global clustering of all transcripts, with specific combinations of Dhn genes providing an excellent indicator of each stress response Data from these studies provide a robust reference data set for abiotic stress
162 citations
TL;DR: This study attempts to identify genes controlling and driving the process of tuber initiation and growth by implementing large-scale transcriptional changes using the newly developed POCI array and will greatly enhance analysis of transcriptional control mechanisms in a wide range of potato research areas.
Abstract: The increasing amount of available expressed gene sequence data makes whole-transcriptome analysis of certain crop species possible. Potato currently has the second largest number of publicly available expressed sequence tag (EST) sequences among the Solanaceae. Most of these ESTs, plus other proprietary sequences, were combined and used to generate a unigene assembly. The set of 246,182 sequences produced 46,345 unigenes, which were used to design a 44K 60-mer oligo array (Potato Oligo Chip Initiative: POCI). In this study, we attempt to identify genes controlling and driving the process of tuber initiation and growth by implementing large-scale transcriptional changes using the newly developed POCI array. Major gene expression profiles could be identified exhibiting differential expression at key developmental stages. These profiles were associated with functional roles in cell division and growth. A subset of genes involved in the regulation of the cell cycle, based on their Gene Ontology classification, exhibit a clear transient upregulation at tuber onset indicating increased cell division during these stages. The POCI array allows the study of potato gene expression on a much broader level than previously possible and will greatly enhance analysis of transcriptional control mechanisms in a wide range of potato research areas. POCI sequence and annotation data are publicly available through the POCI database ( http://pgrc.ipk-gatersleben.de/poci ).
125 citations
TL;DR: The data support the concept of using nearly isogenic ILs for validating and dissecting QTLs into single Mendelian genes and open the gateway for map-based cloning of a grain-weight QTL in wheat.
Abstract: We report the fine mapping of the previously described quantitative trait loci (QTL) for grain weight QTgw.ipk-7D associated with microsatellite marker Xgwm1002-7D by using introgression lines (ILs) carrying introgressions of the synthetic wheat W-7984 in the genetic background of the German winter wheat variety 'Prinz'. The BC(4)F(3) ILs had a 10% increased thousand grain weight compared to the control group and the recurrent parent 'Prinz', and 84.7% of the phenotypic variance could be explained by the segregation of marker Xgwm1002-7D, suggesting the presence of a gene modulating grain weight, which was preliminarily designated gw1. It was possible to delimit the QTL QTgw.ipk-7D to the interval Xgwm295-Xgwm1002, which is located in the most telomeric bin 7DS4-0.61-1.00 in the physical map of wheat chromosome arm 7DS. Furthermore, our data suggest the presence of a novel plant height-reducing locus Rht on chromosome arm 7DS of 'Prinz'. Larger grain and increased plant height may reflect the pleiotropic action of one gene or may be caused by two linked genes. In general, our data support the concept of using nearly isogenic ILs for validating and dissecting QTLs into single Mendelian genes and open the gateway for map-based cloning of a grain-weight QTL in wheat.
125 citations
TL;DR: Control of proteolysis is important for plant growth, development, responses to stress, and defence against insects and pathogens through irreversible inhibition of endogenous and exogenous target proteinases.
Abstract: Control of proteolysis is important for plant growth, development, responses to stress, and defence against insects and pathogens. Members of the serpin protein family are likely to play a critical role in this control through irreversible inhibition of endogenous and exogenous target proteinases. Serpins have been found in diverse species of the plant kingdom and represent a distinct clade among serpins in multicellular organisms. Serpins are also found in green algae, but the evolutionary relationship between these serpins and those of plants remains unknown. Plant serpins are potent inhibitors of mammalian serine proteinases of the chymotrypsin family in vitro but, intriguingly, plants and green algae lack endogenous members of this proteinase family, the most common targets for animal serpins. An Arabidopsis serpin with a conserved reactive centre is now known to be capable of inhibiting an endogenous cysteine proteinase. Here, knowledge of plant serpins in terms of sequence diversity, inhibitory specificity, gene expression and function is reviewed. This was advanced through a phylogenetic analysis of amino acid sequences of expressed plant serpins, delineation of plant serpin gene structures and prediction of inhibitory specificities based on identification of reactive centres. The review is intended to encourage elucidation of plant serpin functions.
120 citations
TL;DR: The microarray data provide insight into the molecular events in the mammary gland at the onset of lactation, indicating the up-regulation of genes involved in milk synthesis concomitant with the inhibition of those related to cell proliferation.
Abstract: The mammary gland undergoes dramatic functional and metabolic changes during the transition from late pregnancy to lactation To better understand the molecular events underlying these changes, we analyzed expression profiles of approximately 23,000 gene transcripts in bovine mammary tissue about day 5 before parturition and day 10 after parturition At the cutoff criteria of the signed fold change >or=2 or
108 citations
TL;DR: A total of 301 and 296 intronless genes from rice and Arabidopsis are conserved among organisms representing the three major domains of life, i.e., archaea, bacteria, and eukaryotes, and are predicted to be involved in housekeeping cellular functions.
Abstract: Intronless genes, a characteristic feature of prokaryotes, constitute a significant portion of the eukaryotic genomes. Our analysis revealed the presence of 11,109 (19.9%) and 5,846 (21.7%) intronless genes in rice and Arabidopsis genomes, respectively, belonging to different cellular role and gene ontology categories. The distribution and conservation of rice and Arabidopsis intronless genes among different taxonomic groups have been analyzed. A total of 301 and 296 intronless genes from rice and Arabidopsis, respectively, are conserved among organisms representing the three major domains of life, i.e., archaea, bacteria, and eukaryotes. These evolutionarily conserved proteins are predicted to be involved in housekeeping cellular functions. Interestingly, among the 68% of rice and 77% of Arabidopsis intronless genes present only in eukaryotic genomes, approximately 51% and 57% genes have orthologs only in plants, and thus may represent the plant-specific genes. Furthermore, 831 and 144 intronless genes of rice and Arabidopsis, respectively, referred to as ORFans, do not exhibit homology to any of the genes in the database and may perform species-specific functions. These data can serve as a resource for further comparative, evolutionary, and functional analysis of intronless genes in plants and other organisms.
101 citations
TL;DR: Evidence is provided that genes involved in ion transport, osmolyte production, and house-keeping functions may play an important role in the primary responses to salt stress in this grass halophyte.
Abstract: The response of a grass halophyte Spartina alterniflora at early stages of salt stress was investigated through generation and systematic analysis of expressed sequence tags (ESTs) from both leaf and root tissues. Random EST sequencing produced 1,227 quality ESTs, which were clustered into 127 contigs, and 368 were singletons. Of the 495 unigenes, 27% represented genes for stress response. Comparison of the 368 singletons against the Oryza sativa gene index showed that >85% of these genes had similarity with the rice unigenes. Moreover, the phylogenetic analysis of an EST similar to myo-inositol 1-phosphate synthase of Spartina and some selected grasses and halophytes showed closeness of Spartina with maize and rice. Transcript abundance analysis involving eight known genes of various metabolic pathways and nine transcription factor genes showed temporal and tissue-dependent variation in expression under salinity. Reverse northern analysis of a few selected unknown and ribosomal genes exhibited much higher abundance of transcripts in response to salt stress. The results provide evidence that, in addition to several unknown genes discovered in this study, genes involved in ion transport, osmolyte production, and house-keeping functions may play an important role in the primary responses to salt stress in this grass halophyte.
100 citations
TL;DR: Investigations suggest that salt-responsive genes identified by this study are candidates for salt-stress tolerance uniquely in wheat and suggest that multiple signal transduction pathways in response to salinity exist in wheat.
Abstract: To identify salt-responsive genes in wheat, global expression analysis of transcripts was carried out using oligo-DNA microarrays. Microarrays have been designed from approximately 32,000 unique wheat genes classified from a large number of expressed sequence tags (ESTs). Two-week-old seedlings of wheat were treated with 150 mM NaCl for 1, 6, and 24 h, and their roots and shoots were separately subjected to analyses. Consequently, 5,996 genes showed changes in expression of more than twofold and were classified into 12 groups according to correlations in expression patterns. These salt-responsive genes were assigned functions using the Gene Ontology (GO). Genes assigned to transcription factor, transcription-regulator activity, and DNA-binding functions were preferentially classified into early response groups. On the other hand, those assigned transferase and transporter activity were classified into late response groups. These data suggest that multiple signal transduction pathways in response to salinity exist in wheat. Transcription factors (TFs) which have been reported as participants in salt-tolerant pathway changed their expression levels in response to salt treatment. Among them, only a few TFs show high sequence homologies to genes in rice. These investigations suggest that salt-responsive genes identified by this study are candidates for salt-stress tolerance uniquely in wheat.
97 citations
TL;DR: Brachypodium BES have more significant matches to ESTs from wheat than rice or maize, although these species have similar sizes of EST collections, and a phylogenetic analysis based on 335 sequences shared among seven grass species further revealed a closer relationship between Brachyp sodium and Triticeae than Brachypodium and Rice or maize.
Abstract: Due in part to its small genome (~350 Mb), Brachypodium distachyon is emerging as a model system for temperate grasses, including important crops like wheat and barley. We present the analysis of 10.9% of the Brachypodium genome based on 64,696 bacterial artificial chromosome (BAC) end sequences (BES). Analysis of repeat DNA content in BES revealed that approximately 11.0% of the genome consists of known repetitive DNA. The vast majority of the Brachypodium repetitive elements are LTR retrotransposons. While Bare-1 retrotransposons are common to wheat and barley, Brachypodium repetitive element sequence-1 (BRES-1), closely related to Bare-1, is also abundant in Brachypodium. Moreover, unique Brachypodium repetitive element sequences identified constitute approximately 7.4% of its genome. Simple sequence repeats from BES were analyzed, and flanking primer sequences for SSR detection potentially useful for genetic mapping are available at http://brachypodium.pw.usda.gov. Sequence analyses of BES indicated that approximately 21.2% of the Brachypodium genome represents coding sequence. Furthermore, Brachypodium BES have more significant matches to ESTs from wheat than rice or maize, although these species have similar sizes of EST collections. A phylogenetic analysis based on 335 sequences shared among seven grass species further revealed a closer relationship between Brachypodium and Triticeae than Brachypodium and rice or maize.
96 citations
TL;DR: Sequence information available in public databases has been used to conduct a survey of A20/AN1 zinc-finger proteins across diverse organisms with a special emphasis on plants, providing interesting insights into their biological function.
Abstract: A20/AN1 zinc-finger domain-containing proteins are well characterized in animals, and their role in regulating the immune response is established. Recently, such A20/AN1 zinc-finger proteins have been reported from plants. These plant proteins are involved in stress response, but their exact molecular mechanism of action is yet to be deciphered. Sequence information available in public databases has been used to conduct a survey of A20/AN1 zinc-finger proteins across diverse organisms with a special emphasis on plants. Domain analysis provides some interesting insights into their biological function, the most important being that A20/AN1 zinc-finger proteins could represent common elements of stress response in plants and animals.
93 citations
TL;DR: The high abundance of SNPs in the barley genome provides avenues for the systematic development of saturated genetic maps and their integration with physical maps.
Abstract: In a panel of seven genotypes, 437 expressed sequence tag (EST)-derived DNA fragments were sequenced. Single nucleotide polymorphisms (SNPs) that were polymorphic between the parents of three mapping populations were mapped by heteroduplex analysis and a genome-wide consensus map comprising 216 EST-derived SNPs and 4 InDel (insertion/deletion) markers was constructed. The average frequency of SNPs amounted to 1/130 bp and 1/107.8 bp for a set of randomly selected and a set of mapped ESTs, respectively. The calculated nucleotide diversities (π) ranged from 0 to 40.0 × 10−3 (average 3.1 × 10−3) and 0.52 × 10−3 to 39.51 × 10–3 (average 4.37 × 10−3) for random and mapped ESTs, respectively. The polymorphism information content value for mapped SNPs ranged from 0.24 to 0.50 with an average of 0.34. As expected, combination of SNPs present in an amplicon (haplotype) exhibited a higher information content ranging from 0.24 to 0.85 with an average of 0.50. Cleaved amplified polymorphic sequence assays (including InDels) were designed for a total of 87 (39.5%) SNP markers. The high abundance of SNPs in the barley genome provides avenues for the systematic development of saturated genetic maps and their integration with physical maps.
TL;DR: It is discussed how cascades involving classical metabolite biotransformation and sequestration processes, alleviation of oxidative stress and promotion of cell survival might contribute to the host response and defence against DON.
Abstract: The Fusarium mycotoxin deoxynivalenol (DON) facilitates fungal spread within wheat tissue and the development of Fusarium head blight disease. The ability of wheat spikelets to resist DON-induced bleaching is genotype-dependent. In wheat cultivar (cv.) CM82036 DON resistance is associated with a quantitative trait locus, Fhb1, located on the short arm of chromosome 3B. Gene expression profiling (microarray and real-time RT-PCR analyses) of DON-treated spikelets of progeny derived from a cross between cv. CM82036 and the DON-susceptible cv. Remus discriminated ten toxin-responsive transcripts associated with the inheritance of DON resistance and Fhb1. These genes do not exclusively map to Fhb1. Based on the putative function of the ten Fhb1-associated transcripts, we discuss how cascades involving classical metabolite biotransformation and sequestration processes, alleviation of oxidative stress and promotion of cell survival might contribute to the host response and defence against DON.
TL;DR: It is concluded that bromoethane-induced cessation of dormancy initiates transcript profiles similar to the natural processes that control dormancy.
Abstract: Meristem dormancy in perennial plants is a developmental process that results in repression of metabolism and growth. The cessation of dormancy results in rapid growth and should be associated with the production of nascent transcripts that encode for gene products controlling for cell division and growth. Dormancy cessation was allowed to progress normally or was chemically induced using bromoethane (BE), and microarray analysis was used to demonstrate changes in specific transcripts in response to dormancy cessation before a significant increase in cell division. Comparison of normal dormancy cessation to BE-induced dormancy cessation revealed a commonality in both up and downregulated transcripts. Many transcripts that decrease as dormancy terminates are inducible by abscisic acid particularly in the conserved BURP domain proteins, which include the RD22 class of proteins and in the storage protein patatin. Transcripts that are associated with an increase in expression encoded for proteins in the oxoglutarate-dependent oxygenase family. We conclude that BE-induced cessation of dormancy initiates transcript profiles similar to the natural processes that control dormancy.
TL;DR: 24 PIP and 11 TIP aquaporin genes from wheat are identified by gene isolation and database searches and provide extensive information for functional studies and developing markers for stress tolerance.
Abstract: Aquaporins, members of major intrinsic proteins (MIPs), transport water across cellular membranes and play vital roles in all organisms. Adversities such as drought, salinity, or chilling affect water uptake and transport, and numerous plant MIPs are reported to be differentially regulated under such stresses. However, MIP genes have been not yet been characterized in wheat, the largest cereal crop. We have identified 24 PIP and 11 TIP aquaporin genes from wheat by gene isolation and database searches. They vary extensively in lengths, numbers, and sequences of exons and introns, and sequences and cellular locations of predicted proteins, but the intron positions (if present) are characteristic. The putative PIP proteins show a high degree of conservation of signature sequences or residues for membrane integration, water transport, and regulation. The TIPs are more diverse, some with potential for water transport and others with various selectivity filters including a new combination. Most genes appear to be expressed as expressed sequence tags, while two are likely pseudogenes. Many of the genes are highly identical to rice but some are unique, and many correspond to genes that show differential expression under salinity and/or drought. The results provide extensive information for functional studies and developing markers for stress tolerance.
TL;DR: Brachypodium will be a useful tool for gene discovery, comparative genomics, and the study of evolutionary relationships among the grasses but will not preclude the need to conduct large-scale genomics experiments in the Triticeae.
Abstract: Brachypodium, a wild temperate grass with a small genome, was recently proposed as a new model organism for the large-genome grasses In this study, we evaluated gene content and microcolinearity between diploid wheat (Triticum monococcum), Brachypodium sylvaticum, and rice at a local genomic region harboring the major wheat domestication gene Q Gene density was much lower in T monococcum (one per 41 kb) because of gene duplication and an abundance of transposable elements within intergenic regions as compared to B sylvaticum (one per 14 kb) and rice (one per 10 kb) For the Q gene region, microcolinearity was more conserved between wheat and rice than between wheat and Brachypodium because B sylvaticum contained two genes apparently not present within the orthologous regions of T monococcum and rice However, phylogenetic analysis of Q and leukotriene A-4 hydrolase-like gene orthologs, which were colinear among the three species, showed that Brachypodium is more closely related to wheat than rice, which agrees with previous studies We conclude that Brachypodium will be a useful tool for gene discovery, comparative genomics, and the study of evolutionary relationships among the grasses but will not preclude the need to conduct large-scale genomics experiments in the Triticeae
TL;DR: A suppressive subtraction hybridization complementary DNA (cDNA) library was constructed from the soybean accession PI200492, which contains Rpp1, after inoculation with two different isolates of P. pachyrhizi that result in susceptible or immune reactions.
Abstract: Soybean rust caused by Phakopsora pachyrhizi Sydow is a devastating foliar disease that has spread to most soybean growing regions throughout the world, including the USA. Four independent rust resistance genes, Rpp1-Rpp4, have been identified in soybean that recognize specific isolates of P. pachyrhizi. A suppressive subtraction hybridization (SSH) complementary DNA (cDNA) library was constructed from the soybean accession PI200492, which contains Rpp1, after inoculation with two different isolates of P. pachyrhizi that result in susceptible or immune reactions. Both forward and reverse SSH were performed using cDNA from messenger RNA pooled from 1, 6, 12, 24, and 48 h post-inoculation. A total of 1,728 SSH clones were sequenced and compared to sequences in GenBank for similarity. Microarray analyses were conducted on a custom 7883 soybean-cDNA clone array encompassing all of the soybean-rust SSH clones and expressed sequence tags from four other soybean cDNA libraries. Results of the microarray revealed 558 cDNA clones differentially expressed in the immune reaction. The majority of the upregulated cDNA clones fell into the functional category of defense. In particular, cDNA clones with similarity to peroxidases and lipoxygenases were prevalent. Downregulated cDNA clones included those with similarity to cell-wall-associated protein, such as extensins, proline-rich proteins, and xyloglucan endotransglycosylases.
TL;DR: This work analyzed the SNPs that can alter the expression and function of transcriptional factor TP53 as a pipeline and proposed modeled structure for the mutant proteins and compared them with the native protein.
Abstract: Single nucleotide polymorphisms (SNPs) are the most common type of genetic variations in humans Understanding the functions of SNPs can greatly help to understand the genetics of the human phenotype variation and especially the genetic basis of human complex diseases The method to identify functional SNPs from a pool, containing both functional and neutral SNPs is challenging by experimental protocols To explore possible relationships between genetic mutation and phenotypic variation, different computational algorithm tools like Sorting Intolerant from Tolerant, Polymorphism Phenotyping, UTRscan, FASTSNP, and PupaSuite were used for prioritization of high-risk SNPs in coding region (exonic nonsynonymous SNPs) and noncoding regions (intronic and exonic 5' and 3'-untranslated region (UTR) SNPs) In this work, we have analyzed the SNPs that can alter the expression and function of transcriptional factor TP53 as a pipeline and for providing a guide to experimental work We identified the possible mutations and proposed modeled structure for the mutant proteins and compared them with the native protein These nsSNPs play a critical role in cancer association studies aiming to explain the disparity in cancer treatment responses as well as to improve the effectiveness of the cancer treatments Our results endorse the study with in vivo experimental protocols
TL;DR: The barley shrunken grain mutant M292 has a high amylose starch phenotype caused by a mutation in the starch synthase IIa gene (SsIIa) located at the starch excess-6 (sex6) locus on chromosome 7H of barley as discussed by the authors.
Abstract: The barley shrunken grain mutant M292 has a novel high-amylose starch phenotype caused by a mutation in the starch synthase IIa gene (SsIIa) located at the starch excess-6 (sex6) locus on chromosome 7H of barley. The loss of SSIIa enzyme activity leads to a decrease in amylopectin synthesis to less than 20% of the levels found in wild-type grains. Detailed composition analysis indicates that the contents of protein, non-starch polysaccharides, lipid, sucrose and hexoses, and fructo-oligosaccharides are increased in mature M292 grain compared to wild type. Using a microarray analysis, we characterize the differences between the transcription profiles of wild-type and mutant barley endosperms at mid-grain fill. The expression changes include genes involved in carbon storage, stress-related genes, and a number of transcripts with unassigned function. The changes in gene expression are discussed in terms of the altered grain composition of the mutant seed.
TL;DR: In this paper, a tiller inhibition mutant with monoculm phenotype was isolated and the mutant gene (tin3) was mapped in the distal region of chromosome arm 3AmL of Triticum monococcum.
Abstract: Changes in plant architecture have been central to the domestication of wild species. Tillering or the degree of branching determines shoot architecture and is a key component of grain yield and/or biomass. Previously, a tiller inhibition mutant with monoculm phenotype was isolated and the mutant gene (tin3) was mapped in the distal region of chromosome arm 3AmL of Triticum monococcum. As a first step towards isolating a candidate gene for tin3, the gene was mapped in relation to physically mapped expressed sequence tags (ESTs) and sequence tag site (STS) markers developed based on synteny with rice. In addition, we investigated the relationship of the wheat region containing tin3 with the corresponding region in rice by comparative genomic analysis. Wheat ESTs that had been previously mapped to deletion bins provided a useful framework to identify closely related rice sequences and to establish the most likely syntenous region in rice for the wheat tin3 region. The tin3 gene was mapped to a 324-kb region spanned by two overlapping bacterial artificial chromosomes (BACs) of rice chromosome arm 1L. Wheat–rice synteny was exceptionally high at the tin3 region despite being located in the high-recombination, gene-rich region of wheat. Identification of tightly linked flanking EST and STS markers to the tin3 gene and its localization to highly syntenic rice BACs will assist in the future development of a high-resolution map and map-based cloning of the tin3 gene.
TL;DR: Although both CCH and CIH regulated numerous genes involved in a wide diversity of processes, the changes in maturational profile, expression stability, and coordination were vastly different between the two treatments, indicating the activation of distinct regulatory mechanisms of gene transcription.
Abstract: Complementary deoxyribonucleic acid microarray data from 36 mice subjected for 1, 2, or 4 weeks of their early life to normal atmospheric conditions (normoxia) or chronic intermittent (CIH) or constant (CCH) hypoxia were analyzed to extract organizational principles of the developing heart transcriptome and determine the integrated response to oxygen deprivation. Although both CCH and CIH regulated numerous genes involved in a wide diversity of processes, the changes in maturational profile, expression stability, and coordination were vastly different between the two treatments, indicating the activation of distinct regulatory mechanisms of gene transcription. The analysis focused on the main regulators of translation and response to stress because of their role in the cardiac hypertrophy and cell survival in hypoxia. On average, the expression of each heart gene was tied to the expression of about 20% of other genes in normoxia but to only 8% in CCH and 9% in CIH, indicating a strong decoupling effect of hypoxia. In contrast to the general tendency, the interlinkages among components of the translational machinery and response to stress increased significantly in CIH and much more in CCH, suggesting a coordinated response to the hypoxic stress. Moreover, the transcriptomic networks were profoundly and differently remodeled by CCH and CIH.
TL;DR: Analysis of transcript profiles obtained from prepubertal heifers provides insight into the molecular mechanisms through which estrogen regulates bovine mammary gland growth and development, supporting the concept that interaction between tissues within the mammary glands promotes mammary epithelial growth.
Abstract: Many attempts have been made to identify estrogen-responsive genes using high-throughput approaches such as microarray, serial analysis of gene expression (SAGE), and in silico prediction. However, few studies have systematically analyzed regulatory networks and pathways affected by estrogen. In this report, we analyzed transcript profiles obtained from 16 prepubertal heifers in a 2 × 2 factorial experiment, with ovarian status (intact or ovariectomized) as the first factor and estrogen treatment as the second (control or estradiol). After 54 h of estrogen treatment, gene expression was evaluated in the parenchyma and fat pad of the bovine mammary gland using a high-density oligonucleotide microarray. The genes significantly regulated by estrogen were subject to pathway and regulatory network analysis using Ingenuity Pathways Analysis software. Approximately 2,344 genes responded significantly to estrogen treatment. Of these, 1016 genes were influenced by estrogen regardless of tissue or ovarian status, while the remaining genes were significant in one of four specific effects of tissue or ovarian status. The canonical pathways significantly regulated by estrogen (P < 0.05) included protein ubiquitination, G2/M cell cycle control, IGF1 signaling, N-glycan biosynthesis, sterol biosynthesis, and oxidative phosphorylation. A total of 23 regulatory networks were identified as estrogen responsive. The results provide insight into the molecular mechanisms through which estrogen regulates bovine mammary gland growth and development, supporting the concept that interaction between tissues within the mammary gland promotes mammary epithelial growth.
TL;DR: Genomics and proteomics analyses were used to identify differences between poor- versus robust-colonizing Campylobacter jejuni isolates, 11168(GS) and A74/C, respectively, and several proteins including cysteine synthase and a Ni/Fe hydrogenase were determined to be differentially present between the two isolates.
Abstract: Campylobacter spp. are one of the leading bacterial etiologic agents of acute human gastroenteritis among industrialized countries. Poultry are implicated as a major source of the organism for human illness; however, the factors involved with colonization of poultry gastrointestinal systems remain unclear. Genomics and proteomics analyses were used to identify differences between poor- versus robust-colonizing Campylobacter jejuni isolates, 11168(GS) and A74/C, respectively. Sequence analyses of subtracted DNA resulted in A74/C-specifc genes similar to a dimethyl sulfoxide reductase, a serine protease, polysaccharide modification proteins, and restriction modification proteins. DNA microarray analyses were performed for comparison of A74/C to the complete genome sequences published for two C. jejuni. A total of 114 genes (7.1%) were determined absent from A74/C relative to those genomes. Additionally, proteomics was completed on both soluble and membrane protein extracts from 11168(GS) and A74/C. Variation in protein expression and physical characteristics such as pI was detected between the two isolates that included the major outer membrane protein, flagella, and aconitate hydratase. Several proteins including cysteine synthase and a Ni/Fe hydrogenase were determined to be differentially present between the two isolates. Finally, DNA hybridization analyses of 19 C. jejuni isolates recovered from chickens and humans worldwide over the past 20 years were performed to determine the distribution of a subset of differentially identified gene sequences.
TL;DR: The studies indicate that the most chloroplast insertions occurred at a nuclear region characterized by a sharp change of repetitive sequence density, and suggest that rice might follow the non-homologous end-joining (NHEJ) repair of double-stranded breaks mechanism, which is suggested to be common to all eukaryotes.
Abstract: Rice (Oryza sativa) is one of three predominant grain crops, and its nuclear and organelle genomes have been sequenced. Following genome analysis revealed many exchanges of DNA sequences between the nuclear and organelle genomes. In this study, a total of 45 chloroplast DNA insertions more than 2 kb in length were detected in rice nuclear genome. A homologous recombination mechanism is expected for those chloroplast insertions with high similarity between their flanking sequences. Only five chloroplast insertions with high sequence similarity between two flanking sequences from an insertion were found in the 45 insertions, suggesting that rice might follow the non-homologous end-joining (NHEJ) repair of double-stranded breaks mechanism, which is suggested to be common to all eukaryotes. Our studies indicate that the most chloroplast insertions occurred at a nuclear region characterized by a sharp change of repetitive sequence density. One potential explanation is that regions such as this might be susceptible target sites or “hotspots” of DNA damage. Our results also suggest that the insertion of retrotransposon elements or non-chloroplast DNA into chloroplast DNA insertions may contribute significantly to their fragmentation process. Moreover, based on chloroplast insertions in nuclear genomes of two subspecies (indica and japonica) of cultivated rice, our results strongly suggest that they diverged during 0.06–0.22 million years ago.
TL;DR: Am amino acid analysis of Phgdh knockout mouse embryos demonstrates that free serine and glycine concentrations are decreased markedly in head samples, reflecting the metabolic changes of serine deficiency found in human patients.
Abstract: d-3-Phosphoglycerate dehydrogenase (Phgdh) is a necessary enzyme for de novo l-serine biosynthesis. Mutations in the human PHGDH cause serine deficiency disorders characterized by severe neurological symptoms including congenital microcephaly and psychomotor retardation. We showed previously that targeted disruption of Phgdh in mice causes overall growth retardation with severe brain microcephaly and leads to embryonic lethality. Here, amino acid analysis of Phgdh knockout (KO) mouse embryos demonstrates that free serine and glycine concentrations are decreased markedly in head samples, reflecting the metabolic changes of serine deficiency found in human patients. To understand the pathogenesis of serine deficiency disorders at the molecular level, we have exploited this animal model to identify altered gene expression patterns using a microarray technology. Comparative microarray analysis of the Phgdh KO and wild-type head at gestational day 13.5 revealed an upregulation of genes involved in transfer RNA aminoacylation, amino acid metabolism, amino acid transport, transcriptional regulation, and translation, and a downregulation of genes involved in transcription in neuronal progenitors and muscle and cartilage development. A computational network analysis software was used to construct transcriptional regulatory networks operative in the Phgdh KO embryos in vivo. These observations suggest that Phgdh inactivation alters transcriptional programs in several regulatory networks.
TL;DR: Express sequence tag (EST) markers from Leymus tiller and rhizomes and mapped sequences aligned to rice chromosome 1 are developed and a SCARECROW-like GRAS-family transcription factor candidate gene was identified in the LeymUS EST library.
Abstract: Leymus cinereus and L. triticoides are large caespitose and rhizomatous perennial grasses, respectively. Previous studies detected quantitative trait loci (QTL) controlling rhizome spreading near the viviparous1 (vp1) gene markers on linkage groups LG3a and LG3b in two families, TTC1 and TTC2, derived from Leymus triticoides × Leymus cinereus hybrids. The wheat tiller inhibition gene (tin3) is located on Triticum monococcum chromosome 3 AmL near vp1. Triticeae group 3 is reportedly collinear with rice chromosome 1, which also contains the maize barren stalk1 and rice lax branching orthogene near vp1. However, previous studies lacked cross-species markers for comparative mapping and showed possible rearrangements of Leymus group 3 in wheat-Leymus racemosus chromosome addition lines. Here, we developed expressed sequence tag (EST) markers from Leymus tiller and rhizomes and mapped sequences aligned to rice chromosome 1. Thirty-eight of 44 informative markers detected loci on Leymus LG3a and LG3b that were collinear with homoeologous sequences on rice chromosome 1 and syntenous in homoeologous group 3 wheat-Leymus and wheat-Thinopyrum addition lines. A SCARECROW-like GRAS-family transcription factor candidate gene was identified in the Leymus EST library, which aligns to the Leymus chromosome group 3 growth habit QTL and a 324-kb rice chromosome 1 region thought to contain the wheat tin3 gene.
TL;DR: This study comprehensively analyzed the expression profile of all the two-component signaling elements identified in rice at various stages of vegetative and reproductive development by employing microarray analysis, indicating their involvement at various levels of hierarchy in abiotic stress signaling.
Abstract: The two-component signaling elements have been implicated in diverse cellular processes in plants. Earlier, we reported the identification, characterization and expression analysis of type-A response regulators in rice. In this study, we have comprehensively analyzed the expression profile of all the two-component signaling elements identified in rice at various stages of vegetative and reproductive development by employing microarray analysis. Most of the components are expressed in all the developmental stages analyzed. A few of these were found to be specifically expressed during certain stages of seed development, suggesting their role in embryo and endosperm development. In addition, some of these components express differentially under various abiotic stress conditions, indicating their involvement at various levels of hierarchy in abiotic stress signaling.
TL;DR: This analysis provides a list of candidate signaling components, which can be analyzed for function in Rpg1-mediated disease resistance, which were activated during the early infection process, before the hypersensitive response or fungal growth inhibition occurred.
Abstract: The dominant barley stem rust resistance gene Rpg1 confers resistance to many but not all pathotypes of the stem rust fungus Puccinia graminis f. sp. tritici (Pgt). Transformation of Rpg1 into susceptible cultivar Golden Promise rendered the transgenic plants resistant to Pgt pathotype MCC but not to Pgt pathotype QCC. Our objective was to identify genes that are induced/repressed during the early stages of pathogen infection to elucidate the molecular mechanisms and role of Rpg1 in defense. A messenger ribonucleic acid expression analysis using the 22K Barley1 GeneChip was conducted in all pair-wise combinations of two isolines (cv. Golden Promise and Rpg1 transgenic line G02-448F-3R) and two Pgt pathotypes (MCC and QCC) across six time points. Analysis showed that a total of 34 probe sets exhibited expression pattern differences between Golden Promise (susceptible) and G02-448F-3R (resistant) infected with Pgt-MCC. A total of 14 probe sets exhibited expression pattern differences between Pgt-MCC (avirulent) and Pgt-QCC (virulent) inoculated onto G02-448F-3R. These differentially expressed genes were activated during the early infection process, before the hypersensitive response or fungal growth inhibition occurred. Our analysis provides a list of candidate signaling components, which can be analyzed for function in Rpg1-mediated disease resistance.
TL;DR: This is the first report on identification of differentially expressed fiber-associated genes in a cotton chromosomal substitution line and a number of genes involved in signal transduction, and protein, nucleic acid, and lipid metabolisms.
Abstract: One of the impediments in the genetic improvement of cotton fiber is the paucity of information about genes associated with fiber development. Availability of chromosome arm substitution line CS-B22sh (chromosome 22 short arm substitution from 3–79 (Gossypium barbadense) into a TM-1 (Gossypium hirsutum) background) provides a novel opportunity to study fiber-associated genes because previous studies revealed this line was associated with some superior fiber quality traits compared to TM-1. We used an integrated approach of suppression subtractive hybridization (SSH), microarray, and real-time reverse transcription-polymerase chain reaction (RT-PCR) technologies to identify the potential genes associated with fiber development. Utilizing mRNAs from 15 days post-anthesis (dpa) fibers, we constructed a SSH cDNA library with chromosome substitution line CS-B22sh as the tester and TM-1 as the driver. The SSH cDNA library was screened using microarrays. Microarray analysis showed that 36 genes were differentially expressed in CS-B22sh 15-dpa fiber compared to TM-1 as confirmed by real time RT-PCR. These genes include two beta-tubulins, an actin, a putative kinesin light chain, a cellulose synthase, glycosyl hydrolase family 3 protein, pyruvate decarboxylase, glycoside hydrolase family 5, GDP-mannose pyrophosphorylase, dynamin-like protein, annexin, and a number of genes involved in signal transduction, and protein, nucleic acid, and lipid metabolisms. To our knowledge, this is the first report on identification of differentially expressed fiber-associated genes in a cotton chromosomal substitution line.
TL;DR: Results show that a one dimensional pool screening can be sufficient to anchor a BAC contig while reducing the number of PCR by 384-fold thereby demonstrating that Elephant is an efficient and cost-effective tool to support physical mapping in large genomes.
Abstract: Anchored physical maps represent essential frameworks for map-based cloning, comparative genomics studies, and genome sequencing projects. High throughput anchoring can be achieved by polymerase chain reaction (PCR) screening of bacterial artificial chromosome (BAC) library pools with molecular markers. However, for large genomes such as wheat, the development of high dimension pools and the number of reactions that need to be performed can be extremely large making the screening laborious and costly. To improve the cost efficiency of anchoring in such large genomes, we have developed a new software named Elephant (electronic physical map anchoring tool) that combines BAC contig information generated by FingerPrinted Contig with results of BAC library pools screening to identify BAC addresses with a minimal amount of PCR reactions. Elephant was evaluated during the construction of a physical map of chromosome 3B of hexaploid wheat. Results show that a one dimensional pool screening can be sufficient to anchor a BAC contig while reducing the number of PCR by 384-fold thereby demonstrating that Elephant is an efficient and cost-effective tool to support physical mapping in large genomes.
TL;DR: It is demonstrated that TMM provides significantly more accurate control of the probability of making type I errors than MMM, and is applied to the well-known leukemia data of Golub et al. (1999).
Abstract: The finite mixture model approach has attracted much attention in analyzing microarray data due to its robustness to the excessive variability which is common in the microarray data. Pan (2003) proposed to use the normal mixture model method (MMM) to estimate the distribution of a test statistic and its null distribution. However, considering the fact that the test statistic is often of t-type, our studies find that the rejection region from MMM is often significantly larger than the correct rejection region, resulting an inflated type I error. This motivates us to propose the t-mixture model (TMM) approach. In this paper, we demonstrate that TMM provides significantly more accurate control of the probability of making type I errors (hence of the familywise error rate) than MMM. Finally, TMM is applied to the well-known leukemia data of Golub et al. (1999). The results are compared with those obtained from MMM.