Showing papers on "Gene published in 1991"
TL;DR: Bulk segregant analysis has several advantages over the use of near-isogenic lines to identify markers in specific regions of the genome and will have widespread application both in those species where selfing is possible and in those that are obligatorily outbreeding.
Abstract: We developed bulked segregant analysis as a method for rapidly identifying markers linked to any specific gene or genomic region. Two bulked DNA samples are generated from a segregating population from a single cross. Each pool, or bulk, contains individuals that are identical for a particular trait or genomic region but arbitrary at all unlinked regions. The two bulks are therefore genetically dissimilar in the selected region but seemingly heterozygous at all other regions. The two bulks can be made for any genomic region and from any segregating population. The bulks are screened for differences using restriction fragment length polymorphism probes or random amplified polymorphic DNA primers. We have used bulked segregant analysis to identify three random amplified polymorphic DNA markers in lettuce linked to a gene for resistance to downy mildew. We showed that markers can be reliably identified in a 25-centimorgan window on either side of the targeted locus. Bulked segregant analysis has several advantages over the use of near-isogenic lines to identify markers in specific regions of the genome. Genetic walking will be possible by multiple rounds of bulked segregation analysis; each new pair of bulks will differ at a locus identified in the previous round of analysis. This approach will have widespread application both in those species where selfing is possible and in those that are obligatorily outbreeding.
4,492 citations
21 Feb 1991
TL;DR: It is demonstrated that in this kindred, which shows linkage to chromosome 21 markers, there is a point mutation in the APP gene that causes an amino-acid substitution close to the carboxy terminus of the β-amyloid peptide.
4,183 citations
TL;DR: The cell cycle is composed of a series of steps which can be negatively or postively regulated by various factors, chief among the negative regulators is the p53 protein, which can lead to cancer.
Abstract: The cell cycle is composed of a series of steps which can be negatively or positively regulated by various factors. Chief among the negative regulators is the p53 protein. Alteration or inactivation of p53 by mutation, or by its interactions with oncogene products of DNA tumour viruses, can lead to cancer. These mutations seem to be the most common genetic change in human cancers.
3,665 citations
TL;DR: DNA from 61 unrelated patients with adenomatous polyposis coli (APC) was examined for mutations in three genes located within a 100 kb region deleted in two of the patients, and data have established that DP2.5 is the APC gene.
2,754 citations
Patent•
17 Dec 1991
TL;DR: In this article, a transgenes containing sequences of unrearranged heterologous human immunoglobulin heavy chains are introduced into a non-human animal, thereby forming a transgenic animal capable of functionally rearranging transgenio-globulin sequences and producing a repertoire of antibodies.
Abstract: The invention relates to transgenic non-human animals capable of producing heterologous antibodies and transgenic non-human animals having inactivated endogenous immunoglobulin genes. In one aspect of the invention, endogenous immunoglobulin genes are suppressed by antisense polynucleotides and/or by antiserum directed against endogenous immunoglobulins. Heterologous antibodies are encoded by immunoglobulin genes not normally found in the genome of that species of non-human animal. In one aspect of the invention, one or more transgenes containing sequences of unrearranged heterologous human immunoglobulin heavy chains are introduced into a non-human animal thereby forming a transgenic animal capable of functionally rearranging transgenic immunoglobulin sequences and producing a repertoire of antibodies of various isotypes encoded by human immunoglobulin genes. Such heterologous human antibodies are produced in B-cells which are thereafter immortalized, e.g., by fusing with an immortalizing cell line such as a myeloma or by manipulating such B-cells by other techniques to perpetuate a cell line capable of producing a monoclonal heterologous antibody. The invention also relates to heavy and light chain immunoglobulin transgenes for making such transgenic non-human animals as well as methods and vectors for disrupting endogenous immunoglobulin loci in the transgenic animal.
2,411 citations
TL;DR: Automated partial DNA sequencing was conducted on more than 600 randomly selected human brain complementary DNA (cDNA) clones to generate expressed sequence tags (ESTs), which will facilitate the tagging of most human genes in a few years at a fraction of the cost of complete genomic sequencing.
Abstract: Automated partial DNA sequencing was conducted on more than 600 randomly selected human brain complementary DNA (cDNA) clones to generate expressed sequence tags (ESTs). ESTs have applications in the discovery of new human genes, mapping of the human genome, and identification of coding regions in genomic sequences. Of the sequences generated, 337 represent new genes, including 48 with significant similarity to genes from other organisms, such as a yeast RNA polymerase II subunit; Drosophila kinesin, Notch, and Enhancer of split; and a murine tyrosine kinase receptor. Forty-six ESTs were mapped to chromosomes after amplification by the polymerase chain reaction. This fast approach to cDNA characterization will facilitate the tagging of most human genes in a few years at a fraction of the cost of complete genomic sequencing, provide new genetic markers, and serve as a resource in diverse biological research fields.
2,375 citations
TL;DR: The APC gene was identified in a contig initiated from the MCC gene and was found to encode an unusually large protein, and these two closely spaced genes encode proteins predicted to contain coiled-coil regions, which were also expressed in a wide variety of tissues.
Abstract: Recent studies suggest that one or more genes on chromosome 5q21 are important for the development of colorectal cancers, particularly those associated with familial adenomatous polyposis (FAP). To facilitate the identification of genes from this locus, a portion of the region that is tightly linked to FAP was cloned. Six contiguous stretches of sequence (contigs) containing approximately 5.5 Mb of DNA were isolated. Subclones from these contigs were used to identify and position six genes, all of which were expressed in normal colonic mucosa. Two of these genes (APC and MCC) are likely to contribute to colorectal tumorigenesis. The MCC gene had previously been identified by virtue of its mutation in human colorectal tumors. The APC gene was identified in a contig initiated from the MCC gene and was found to encode an unusually large protein. These two closely spaced genes encode proteins predicted to contain coiled-coil regions. Both genes were also expressed in a wide variety of tissues. Further studies of MCC and APC and their potential interaction should prove useful for understanding colorectal neoplasia.
2,364 citations
TL;DR: This article showed that VEGF is produced by cultured vascular smooth muscle cells by polymerase chain reaction and cDNA cloning, and showed that the three forms of the human vascular endothelial growth factor (VEGF) protein chain predicted from these coding regions are 189, 165, and 121 amino acids in length.
1,992 citations
TL;DR: The nucleotide sequence of the RNA genome of the human hepatitis C virus has been determined and significant genome diversity is apparent within the putative 5' structural gene region of different HCV isolates, suggesting the presence of closely related but distinct viral genotypes.
Abstract: The nucleotide sequence of the RNA genome of the human hepatitis C virus (HCV) has been determined from overlapping cDNA clones. The sequence (9379 nucleotides) has a single large open reading frame that could encode a viral polyprotein precursor of 3011 amino acids. While there as little overall amino acid and nucleotide sequence homology with other viruses, the 5' HCV nucleotide sequence upstream of this large open reading frame has substantial similarity to the 5' termini of pestiviral genomes. The polyprotein also has significant sequence similarity to helicases encoded by animal pestiviruses, plant potyviruses, and human flaviviruses, and it contains sequence motifs widely conserved among viral replicases and trypsin-like proteases. A basic, presumed nucleocapsid domain is located at the N terminus upstream of a region containing numerous potential N-linked glycosylation sites. These HCV domains are located in the same relative position as observed in the pestiviruses and flaviviruses and the hydrophobic profiles of all three viral polyproteins are similar. These combined data indicate that HCV is an unusual virus that is most related to the pestiviruses. Significant genome diversity is apparent within the putative 5' structural gene region of different HCV isolates, suggesting the presence of closely related but distinct viral genotypes.
1,837 citations
TL;DR: It is shown that the locus on chromosome 9 contains a gene highly homologous to the Drosophila gene Notch, which may be important for normal lymphocyte function and that alteration of TAN-1 may play a role in the pathogenesis of some T cell neoplasms.
1,781 citations
TL;DR: The expression of the TIS10 gene appears to be highly cell type-restricted in cultured cell lines; of 12 cell lines tested under superinducing conditions, only the rodent embryonic Swiss 3T3 and Rat1 cell lines expressed TIS12 gene.
TL;DR: It is demonstrated that IGF-II is indispensable for normal embryonic growth and that the IGF- II gene is subject to tissue-specific parental imprinting.
TL;DR: The results indicate that nef is required for maintaining high virus loads during the course of persistent infection in vivo and for full pathologic potential, and should become a target for antiviral drug development.
TL;DR: Intercrossing of heterozygotes from 24 strains that express beta-galactosidase identified 9 strains in which homozygosity leads to an embryonic lethality, suggesting that a substantial proportion of mammalian genes identified by this approach are not essential for development.
Abstract: A general strategy for selecting insertion mutations in mice has been devised. Constructs lacking a promoter and including a beta-galactosidase gene, or a reporter gene encoding a protein with both beta-galactosidase and neomycin phosphotransferase activity, were designed so that activation of the reporter gene depends on its insertion within an active transcription unit. Such insertion events create a mutation in the tagged gene and allow its expression to be followed by beta-galactosidase activity. Introduction of promoter trap constructs into embryonic stem (ES) cells by electroporation or retroviral infection has led to the derivation of transgenic lines that show a variety of beta-galactosidase expression patterns. Intercrossing of heterozygotes from 24 strains that express beta-galactosidase identified 9 strains in which homozygosity leads to an embryonic lethality. Because no overt phenotype was detected in the remaining strains, these results suggest that a substantial proportion of mammalian genes identified by this approach are not essential for development.
TL;DR: It is shown that the onset of SAR correlates with the coordinate induction of nine classes of mRNAs, consistent with the hypothesis that induced resistance results at least partially from coordinate expression of these SAR genes.
Abstract: In a variety of plant species, the development of necrotic lesions in response to pathogen infection leads to induction of generalized disease resistance in uninfected tissues. A well-studied example of this "immunity" reaction is systemic acquired resistance (SAR) in tobacco. SAR is characterized by the development of a disease-resistant state in plants that have reacted hypersensitively to previous infection by tobacco mosaic virus. Here, we show that the onset of SAR correlates with the coordinate induction of nine classes of mRNAs. Salicylic acid, a candidate for the endogenous signal that activates the resistant state, induces expression of the same "SAR genes." A novel synthetic immunization compound, methyl-2,6-dichloroisonicotinic acid, also induces both resistance and SAR gene expression. These observations are consistent with the hypothesis that induced resistance results at least partially from coordinate expression of these SAR genes. A model is presented that ties pathogen-induced necrosis to the biosynthesis of salicylic acid and the induction of SAR.
TL;DR: The purpose of this study is to discuss some of the results and concepts resulting from genetic approaches to identify the genes that appear to be involved in providing negative signals for cell proliferation and behavior.
TL;DR: The methods described in this chapter permit the manipulation of virtually any cloned yeast chromosomal sequence by virtue of the fact that DNA transformed into yeast integrates into the chromosome by homologous recombination.
Abstract: The methods described in this chapter permit the manipulation of virtually any cloned yeast chromosomal sequence by virtue of the fact that DNA transformed into yeast integrates into the chromosome by homologous recombination. Furthermore, double-strand breaks in transforming DNA stimulate recombination and can be used to target integration events. This allows simple one-step gene disruption methods using yeast selectable markers. The availability of counterselectable markers makes it possible to replace chromosomal sequences with mutant alleles that cannot be directly selected. Finally, these same methods can be used to rescue chromosomal alleles on plasmids for subsequent molecular analysis.
TL;DR: The occurrence of a second allelic variant at codon 717 linked to the Alzheimer's phenotype supports the hypothesis that they are pathogenic mutations.
Abstract: A MUTATION at codon 717 of the β-amyloid precursor protein gene has been found to cosegregate with familial Alzheimer's disease in a single family1. This mutation has been reported in a further five out of ∼ 100 families multiply affected by Alzheimer's disease1–4. We have identified another family, F19, in which we have detected linkage between the β-amyloid precursor protein gene and Alzheimer's disease. Direct sequencing of exon 17 (ref. 5) in affected individuals from this family has revealed a base change producing a Val → Gly substitution, also at codon 717. The occurrence of a second allelic variant at codon 717 linked to the Alzheimer's phenotype supports the hypothesis that they are pathogenic mutations.
TL;DR: This work presents an hypothesis that accounts for many of the observed effects of imprinting in mammals and relates them to similar observations in plants and has implications for studies of X-chromosome inactivation and a range of human diseases.
TL;DR: An RNase protection assay is used that can distinguish between H19 alleles in four subspecies of Mus, to demonstrate that the H19 gene is parentally imprinted, with the active copy derived from the mother.
Abstract: THE mouse H19 gene encodes one of the most abundant RNAs in the developing mouse embryo It is expressed at the blastocyst stage of development, and accumulates to high levels in tissues of endodermal and mesodermal origin (H Kim, unpublished result) After birth the gene is expressed in all tissues except skeletal muscle It lacks a common open reading frame in the 25-kilobase RNA, but has considerable nucleotide sequence similarity between the genes of rodents and humans Expression of the gene in transgenic mice results in late prenatal lethality, suggesting that the dosage of its gene product is strictly controlled The H19 gene maps to the distal segment of mouse chromosome 7, in a region that is parentally imprinted, a process by which genes are differentially expressed on the maternal and paternal chromosomes We have now used an RNase protection assay that can distinguish between H19 alleles in four subspecies of Mus, to demonstrate that the H19 gene is parentally imprinted, with the active copy derived from the mother This assay will be of general use in assaying allele-specific gene expression
TL;DR: Data suggest that a function of p53 may be mediated by its ability to bind to specific DNA sequences in the human genome, and that this activity is altered by mutations that occur in human tumors.
Abstract: The tumor-suppressor gene p53 is altered by missense mutation in numerous human malignancies. However, the biochemical properties of p53 and the effect of mutation on these properties are unclear. A human DNA sequence was identified that binds specifically to wild-type human p53 protein in vitro. As few as 33 base pairs were sufficient to confer specific binding. Certain guanines within this 33-base pair region were critical, as methylation of these guanines or their substitution with thymine-abrogated binding. Human p53 proteins containing either of two missense mutations commonly found in human tumors were unable to bind significantly to this sequence. These data suggest that a function of p53 may be mediated by its ability to bind to specific DNA sequences in the human genome, and that this activity is altered by mutations that occur in human tumors.
TL;DR: The 3 angstrom resolution crystal structure of the Escherichia coli catabolite gene activator protein (CAP) complexed with a 30-base pair DNA sequence shows that the DNA is bent by 90 degrees.
Abstract: The 3 angstrom resolution crystal structure of the Escherichia coli catabolite gene activator protein (CAP) complexed with a 30-base pair DNA sequence shows that the DNA is bent by 90 degrees. This bend results almost entirely from two 40 degrees kinks that occur between TG/CA base pairs at positions 5 and 6 on each side of the dyad axis of the complex. DNA sequence discrimination by CAP derives both from sequence-dependent distortion of the DNA helix and from direct hydrogen-bonding interactions between three protein side chains and the exposed edges of three base pairs in the major groove of the DNA. The structure of this transcription factor--DNA complex provides insights into possible mechanisms of transcription activation.
TL;DR: Findings on the genetic organization and expression strategy of HEV suggest that it is the prototype human pathogen for a new class of RNA virus or perhaps a separate genus within the Caliciviridae family.
TL;DR: A modest revision of the initially proposed and updated and updated nomenclature system based on evolution of the superfamily P450 is proposed.
Abstract: We provide here a list of 154 P450 genes and seven putative pseudogenes that have been characterized as of October 20, 1990. These genes have been described in a total of 23 eukaryotes (including nine mammalian and one plant species) and six prokaryotes. Of 27 gene families so far described, 10 exist in all mammals. These 10 families comprise 18 subfamilies, of which 16 and 14 have been mapped in the human and mouse genomes, respectively; to date, each subfamily appears to represent a cluster of tightly linked genes. We propose here a modest revision of the initially proposed (Nebert et al., DNA 6, 1–11,1987) and updated (Nebert et al., DNA 8, 1–13, 1989) nomenclature system based on evolution of the superfamily. For the gene we recommend that the italicized root symbol CYP for human (Cyp for mouse), representing cytochrome P450, be followed by an Arabic number denoting the family, a letter designating the subfamily (when two or more exist), and an Arabic numeral representing the individual gene ...
TL;DR: A 256-base-pair region of 3' flanking sequence was shown by DNase I protection and electrophoretic mobility shift assays to bind four or more different nuclear factors, at least two of which are induced by anemia in both liver and kidney, and the region functioned as hypoxia-inducible enhancer in transient expression assays as mentioned in this paper.
Abstract: Human erythropoietin gene expression in liver and kidney is inducible by anemia or hypoxia. DNase I-hypersensitive sites were identified 3' to the human erythropoietin gene in liver nuclei. A 256-base-pair region of 3' flanking sequence was shown by DNase I protection and electrophoretic mobility-shift assays to bind four or more different nuclear factors, at least two of which are induced by anemia in both liver and kidney, and the region functioned as a hypoxia-inducible enhancer in transient expression assays. These results provide insight into the molecular basis for the regulation of gene expression by a fundamental physiologic stimulus, hypoxia.
TL;DR: The p53 mutations are the first genetic alterations demonstrated to occur in a high proportion of primary invasive bladder cancers, and Detection of such mutations ex vivo has clinical implications for monitoring individuals whose tumor cells are shed extracorporeally.
Abstract: Although bladder cancers are very common, little is known about their molecular pathogenesis. In this study, invasive bladder cancers were evaluated for the presence of gene mutations in the p53 suppressor gene. Of 18 tumors evaluated, 11 (61 percent) were found to have genetic alterations of p53. The alterations included ten point mutations resulting in single amino acid substitutions, and one 24-base pair deletion. In all but one case, the mutations were associated with chromosome 17p allelic deletions, leaving the cells with only mutant forms of the p53 gene products. Through the use of the polymerase chain reaction and oligomer-specific hybridization, p53 mutations were identified in 1 to 7 percent of the cells within the urine sediment of each of three patients tested. The p53 mutations are the first genetic alterations demonstrated to occur in a high proportion of primary invasive bladder cancers. Detection of such mutations ex vivo has clinical implications for monitoring individuals whose tumor cells are shed extracorporeally.
TL;DR: Three novel genes have been identified, which are sufficiently distantly related to the other members of the cyclin family and to each other as to constitute three new classes of cyclins.
TL;DR: Gene targeting in mouse embryo-derived stem cells has been used to disrupt the homeobox gene hox-1.5, and homozygotes are athymic, aparathyroid, have reduced thyroid and submaxillary tissue and exhibit a wide range of throat abnormalities.
Abstract: Gene targeting in mouse embryo-derived stem cells has been used to disrupt the homeobox gene hox-1.5. Mice heterozygous at the hox-1.5 locus appear normal, whereas hox-1.5-/hox-1.5- mice die at or shortly after birth. These homozygotes are athymic, aparathyroid, have reduced thyroid and submaxillary tissue and exhibit a wide range of throat abnormalities. In addition, they often feature defects of the heart and arteries as well as craniofacial abnormalities. These deficiencies are remarkably similar to the pathology of the human congenital disorder DiGeorge's syndrome.
TL;DR: The hypothesis that the inactivation of the normal functions of the tumor-suppressor proteins pRB and p53 are important steps in human cervical carcinogenesis, either by mutation or from complex formation with the HPV E6 and E7 oncoproteins is supported.
Abstract: Human cervical carcinoma cell lines that were either positive or negative for human papillomavirus (HPV) DNA sequences were analyzed for evidence of mutation of the p53 and retinoblastoma genes. Each of five HPV-positive cervical cancer cell lines expressed normal pRB and low levels of wild-type p53 proteins, which are presumed to be altered in function as a consequence of association with HPV E7 and E6 oncoproteins, respectively. In contrast, mutations were identified in the p53 and RB genes expressed in the C-33A and HT-3 cervical cancer cell lines, which lack HPV DNA sequences. Mutations in the p53 genes mapped to codon 273 and codon 245 in the C33-A and HT-3 cell lines, respectively, located in the highly conserved regions of p53, where mutations appear in a variety of human cancers. Mutations in RB occurred at splice junctions, resulting in in-frame deletions, affecting exons 13 and 20 in the HT-3 and C-33A cell lines, respectively. These mutations resulted in aberrant proteins that were not phosphorylated and were unable to complex with the adenovirus E1A oncoprotein. These results support the hypothesis that the inactivation of the normal functions of the tumor-suppressor proteins pRB and p53 are important steps in human cervical carcinogenesis, either by mutation or from complex formation with the HPV E6 and E7 oncoproteins.
TL;DR: Bacteriophage T7 lysozyme can reduce basal activity from an inducible gene for T7 RNA polymerase and allow relatively toxic genes to be established in the same cell under control of a T7 promoter.