Showing papers on "Upstream activating sequence published in 2007"

Targeting neural circuitry in zebrafish using GAL4 enhancer trapping

Abstract: We present a pilot enhancer trap screen using GAL4 to drive expression of upstream activator sequence (UAS)-linked transgenes in expression patterns dictated by endogenous enhancers in zebrafish. The patterns presented include expression in small subsets of neurons throughout the larval brain, which in some cases persist into adult. Through targeted photoconversion of UAS-driven Kaede and variegated expression of UAS-driven GFP in single cells, we begin to characterize the cellular components of labeled circuits.

Housekeeping genes tend to show reduced upstream sequence conservation.

Abstract: Background: Understanding the constraints that operate in mammalian gene promoter sequences is of key importance to understand the evolution of gene regulatory networks. The level of promoter conservation varies greatly across orthologous genes, denoting differences in the strength of the evolutionary constraints. Here we test the hypothesis that the number of tissues in which a gene is expressed is related in a significant manner to the extent of promoter sequence conservation. Results: We show that mammalian housekeeping genes, expressed in all or nearly all tissues, show significantly lower promoter sequence conservation, especially upstream of position -500 with respect to the transcription start site, than genes expressed in a subset of tissues. In addition, we evaluate the effect of gene function, CpG island content and protein evolutionary rate on promoter sequence conservation. Finally, we identify a subset of transcription factors that bind to motifs that are specifically over-represented in housekeeping gene promoters. Conclusion: This is the first report that shows that the promoters of housekeeping genes show reduced sequence conservation with respect to genes expressed in a more tissue-restricted manner. This is likely to be related to simpler gene expression, requiring a smaller number of functional cis-regulatory motifs.

SOX9cre1, a cis-acting regulatory element located 1.1 Mb upstream of SOX9, mediates its enhancement through the SHH pathway.

Abstract: SOX9 is a temporal and tissue-specific transcription factor involved in male sexual development and bone formation. Haploinsufficiency of SOX9 is known to cause campomelic dysplasia (CD). CD cases without SOX9 coding region mutations have been described in association with translocations that have breakpoints mapping as far as 932 kb upstream from the gene. These rearrangements suggest that position effects acting from a great distance regulate SOX9 gene expression. Studies of one such case (900 kb upstream to SOX9) have led to the delineation of a potential 2.1 kb cis-acting regulatory element 1.1 Mb upstream of SOX9, termed SOX9cre1. We investigated the role of this putative regulator in SOX9 expression. SOX9cre1 increases the activity of a minimal SOX9 promoter in reporter constructs in a dose-dependent and tissue-specific manner, consistent with an enhancer role. In silico studies identify a putative binding site within SOX9cre1 for GLI1, a downstream mediator of sonic hedgehog (SHH). Furthermore, the stimulation of primary human chondrocyte cells in culture with SHH increases endogenous SOX9 expression 3-fold. Electrophoresis mobility shift assay (EMSA) studies that demonstrate physical interactions between the GLI1 transcription factor and a putative binding site within SOX9cre1, as well as experiments in which reporter constructs are co-transfected with GLI1, suggest a direct interaction between GLI1 and SOX9cre1. GLI1-SOX9cre1 interactions are verified in chromatin immunoprecipitation experiments. These data support a direct molecular link between the Hh signaling pathway and SOX9 regulation, wherein SHH stimulates SOX9 through its mediator GLI1, and are consistent with a mechanism of SOX9 regulation through distal chromatin interactions.

Characterization of Z-DNA as a nucleosome-boundary element in yeast Saccharomyces cerevisiae

Abstract: In this article, the effect of a d(CG) DNA dinucleotide repeat sequence on RNA polymerase II transcription is examined in yeast Saccharomyces cerevisiae Our previous report shows that a d(CG)n dinucleotide repeat sequence located proximally upstream of the TATA box enhances transcription from a minimal CYC1 promoter in a manner that depends on its surrounding negative supercoiling Here, we demonstrate that the d(CG)9 repeat sequence stimulates gene activity by forming a Z-DNA secondary structure Furthermore, the extent of transcriptional enhancement by Z-DNA is promoter-specific and determined by its separation distance relative to the TATA box The stimulatory effect exerted by promoter proximal Z-DNA is not affected by helical phasing relative to the TATA box, suggesting that Z-DNA effects transcription without interacting with the general transcription machinery by looping-out the intervening DNA A nucleosome-scanning assay reveals that the d(CG)9 repeat sequence in the Z conformation blocks nucleosome formation, and it is found in the linker DNA with two flanking nucleosomes This result suggests that Z-DNA formation proximally upstream of a promoter is sufficient to demarcate the boundaries of its neighboring nucleosomes, which produces transcriptionally favorable locations for the TATA box near the nucleosomal DNA-entry site and at dyad positions on the nucleosome These findings suggest that Z-DNA formation in chromatin is a part of the “genomic code” for nucleosome positioning in vivo

Transcriptional regulation of phospholipid biosynthesis is linked to fatty acid metabolism by an acyl-coa-binding-protein-dependent mechanism in Saccharomyces cerevisiae

Abstract: In the present study, we have used DNA microarray and quantitative real-time PCR analysis to examine the transcriptional changes that occur in response to cellular depletion of the yeast acyl-CoA-binding protein, Acb1p. Depletion of Acb1p resulted in the differential expression of genes encoding proteins involved in fatty acid and phospholipid synthesis (e.g. FAS1, FAS2, ACC1, OLE1, INO1 and OPI3), glycolysis and glycerol metabolism (e.g. GPD1 and TDH1), ion transport and uptake (e.g. ITR1 and HNM1) and stress response (e.g. HSP12, DDR2 and CTT1). In the present study, we show that transcription of the INO1 gene, which encodes inositol-3-phosphate synthase, cannot be fully repressed by inositol and choline, and UASINO1 (inositol-sensitive upstream activating sequence)-driven transcription is enhanced in Acb1p-depleted cells. In addition, the reduction in inositol-mediated repression of INO1 transcription observed after depletion of Acb1p appeared to be independent of the transcriptional repressor, Opi1p. We also demonstrated that INO1 and OPI3 expression can be normalized in Acb1p-depleted cells by the addition of high concentrations of exogenous fatty acids, or by the overexpression of FAS1 or ACC1. Together, these findings revealed an Acb1p-dependent connection between fatty acid metabolism and transcriptional regulation of phospholipid biosynthesis in yeast. Finally, expression of an Acb1p mutant which is unable to bind acyl-CoA esters could not normalize the transcriptional changes caused by Acb1p depletion. This strongly implied that gene expression is modulated either by the Acb1p–acyl-CoA ester complex directly or by its ability to donate acyl-CoA esters to utilizing systems.

GAL4/UAS targeted gene expression for studying Drosophila Hedgehog signaling.

Abstract: The GAL4/upstream activating sequence (UAS) system is one of the most powerful tools for targeted gene expression. It is based on the properties of the yeast GAL4 transcription factor which activates transcription of its target genes by binding to UAS cis-regulatory sites. In Drosophila, the two components are carried in separate lines allowing for numerous combinatorial possibilities. The driver lines provide tissue-specific GAL4 expression and the responder lines carry the coding sequence for the gene of interest under the control of UAS sites. In this chapter, the basic GAL4/UAS system and its extensions, namely those allowing precise temporal control and reversible expression, are described. In addition, a list of GAL4 and UAS lines and schematic maps of GAL4 and UAS vectors useful in the study of Hedgehog (Hh) signaling is given. Finally, uses of the GAL4/UAS system to resolve some of the questions addressed in the study of the Hh pathway are presented.

Recruitment of coregulator complexes to the β‐globin gene locus by TFII‐I and upstream stimulatory factor

Abstract: Upstream stimulatory factor and TFII-I are ubiquitously expressed helix-loop-helix transcription factors that interact with E-box sequences and or initiator elements. We previously demonstrated that upstream stimulatory factor is an activator of beta-globin gene expression whereas TFII-I is a repressor. In the present study, we demonstrate that upstream stimulatory factor interacts with the coactivator p300 and that this interaction is restricted to erythroid cells expressing the adult beta-globin gene. Furthermore, we demonstrate that Suz12, a component of the polycomb repressor complex 2, is recruited to the beta-globin gene. Reducing expression of Suz12 significantly activates beta-globin gene expression in an erythroid cell line with an embryonic phenotype. Suz12 also interacts with the adult beta-globin gene during early stages of erythroid differentiation of mouse embryonic stem cells. Our data suggest that TFII-I contributes to the recruitment of the polycomb repressor complex 2 complex to the beta-globin gene. Together, these data demonstrate that the antagonistic activities of upstream stimulatory factor and TFII-I on beta-globin gene expression are mediated at least in part by protein complexes that render the promoter associated chromatin accessible or inaccessible for the transcription complex.

The MN1 oncoprotein activates transcription of the IGFBP5 promoter through a CACCC-rich consensus sequence

Abstract: The IGF-binding protein (IGFBP) family consists of six proteins that are expressed and secreted in different tissues. The proteins are regulators of physiological processes throughout the body by modulating the activity of IGF-I and IGF-II. In this article, we describe the coordinated expression of IGFBP5 and MN1 in meningiomas. MN1 is a transcriptional co-activator and we show that MN1 stimulates the IGFBP5 promoter in Hep3B cells. A CACCC-containing sequence, located 140 bp upstream of the transcription start site of the promoter, is required for MN1 action. This sequence matches with the CACCCAC consensus sequence that was selected in an oligonucleotide selection assay performed for MN1. The CACCC element has also been shown to be important for induction of the IGFBP5 promoter by retinoic acid (RA) and progesterone (Pg). We were unable to confirm the effect of Pg on the promoter in Hep3B and U2-osteosarcoma cells regardless of the presence of MN1. On the other hand, we show that induction of the promoter by RA depends on co-expressed MN1 in Hep3B cells. MN1TEL, a leukemia-related fusion protein containing parts of the MN1 and TEL (ETV6) genes, is capable of stimulating the IGFBP5 promoter but is unable to cooperate with RA in Hep3B cells. This suggests that the effects of RA can be negatively affected in leukemias caused by MN1TEL.

Combination of the ALCR/alcA ethanol switch and GAL4/VP16-UAS enhancer trap system enables spatial and temporal control of transgene expression in Arabidopsis.

Abstract: The experimental control of gene expression in specific tissues or cells at defined time points is a useful tool for the analysis of gene function. GAL4/VP16-UAS enhancer trap lines can be used to selectively express genes in specific tissues or cells, and an ethanol-inducible system can help to control the time of expression. In this study, the combination of the two methods allowed the successful regulation of gene expression in both time and space. For this purpose, a binary vector, 962-UAS::GUS, was constructed in which the ALCR activator and beta-glucuronidase (GUS) reporter gene were placed under the control of upstream activator sequence (UAS) elements and the alcA response element, respectively. Three different GAL4/VP16-UAS enhancer trap lines of Arabidopsis were transformed, resulting in transgenic plants in which GUS activity was detected only on ethanol induction and exclusively in the predicted tissues of the enhancer trap lines. As a library of different enhancer trap lines with distinct green fluorescent protein (GFP) patterns exist, transformation with a similar vector, in which GUS is replaced by another gene, would enable the control of the time and place of transgene expression. We have constructed two vectors for easy cloning of the gene of interest, one with a polylinker site and one that is compatible with the GATEWAY vector conversion system. The method can be extended to other species when enhancer trap lines become available.

Architecture of the sporulation-specific Cdc14 promoter from the oomycete Phytophthora infestans.

Abstract: The Cdc14 gene of Phytophthora infestans is transcribed specifically during sporulation, with no mRNA detectable in vegetative hyphae, and is required for sporangium development To unravel the mechanisms regulating its transcription, mutated Cdc14 promoters plus chimeras of selected Cdc14 sequences and a minimal promoter were tested in stable transformants This revealed that a tandem repeat of three copies of the motif CTYAAC, located between 67 and 90 nucleotides (nt) upstream of the major transcription start site, is sufficient to determine sporulation-specific expression All three repeats need to be present for activity, suggesting that they bind a transcription factor through a cooperative mechanism Electrophoretic mobility shift assays indicated that the CTYAAC repeats are specifically bound by a protein in nuclear extracts Evidence was also obtained for a second region within the promoter that activates Cdc14 transcription during sporulation which does not involve those repeats The CTYAAC motif also affects the specificity of transcription initiation Wild-type Cdc14 is transcribed from a major start site and minor site(s) located about 100 nt upstream of the major site However, stepwise mutations through the CTYAAC triad caused a graded shift to the upstream sites, as did mutating bases surrounding the major start site; transcripts initiated from the upstream site remained sporulation specific Replacing the Cdc14 initiation region with the Inr-like region of the constitutive Piexo1 gene had no apparent effect on the pattern of transcription Therefore, this study reports the first motif determining sporulation-induced transcription in oomycetes and helps define oomycete core promoters

Coupling the GAL4 UAS system with alcR for versatile cell type‐specific chemically inducible gene expression in Arabidopsis

Abstract: The Aspergillus alc regulon encodes a transcription factor, ALCR, which regulates transcription from cognate promoters such as alcA(p). In the presence of suitable chemical inducers, ALCR activates gene expression from alcA(p). The alc regulon can be transferred to other species and can be used to control the expression of reporter, metabolic and developmental genes in response to low-level ethanol exposure. In this paper, we describe a versatile system for targeting the alc regulon to specific cell types in Arabidopsis by driving ALCR expression from the GAL4 upstream activator sequence (UAS). Large numbers of Arabidopsis lines are available in which GAL4 is expressed in a variety of spatial patterns and, in turn, drives the expression of any gene cloned downstream of the UAS. We have used a previously characterized line that directs gene expression to the endosperm to demonstrate spatially restricted ethanol-inducible gene expression. We also show that the domain of inducible gene expression can easily be altered by crossing the UAS::ALCR cassette into different driver lines. We conclude that this gene switch can be used to drive gene expression in a highly responsive, but spatially restricted, manner.

Methods for increasing expression of genes in a fungal cell

Abstract: The present invention relates to methods for producing a polypeptide, comprising: (a) cultivating a fungal host cell in a medium conducive for the production of the polypeptide, wherein the fungal host cell comprises a first polynucleotide comprising a nucleic acid sequence encoding the polypeptide operably linked to a copper-inducible promoter sequence comprising a copper-responsive upstream activation sequence activated by a copper-dependent trans-acting transcription factor and a second polynucleotide comprising one or more (several) additional copper-responsive upstream activation sequences operably linked upstream to the promoter sequence, wherein the promoter sequence is foreign to the nucleic acid sequence encoding the polypeptide and the copper-responsive upstream activation sequences are responsible for copper-induced transcription of the promoter sequence, and a third polynucleotide comprising at least one copy of a gene encoding the copper-dependent trans-acting transcription factor; and (b) isolating the polypeptide from the cultivation medium.

Real-time monitoring of functional interactions between upstream and core promoter sequences in living cells of sea urchin embryos

Abstract: There are some functional compatibilities between upstream and core promoter sequences for transcriptional activation in yeast, Drosophila and mammalian cells. Here we examined whether similar compatibilities exist in sea urchin embryos, and if so, whether they are dynamically regulated during early development. Two reporter plasmids, each containing a test promoter conjugated to either CFP or YFP, were concurrently introduced into embryos, and their expression patterns were studied by fluorescence microscopy. The upstream sequence of the Hemicentrotus pulcherrimus (Hp) OtxE promoter drives the expression of its own core promoter and that of Strongylocentrotus purpuratus (Sp) Spec2a in different embryonic regions, especially at the late gastrula stage. Interestingly, when the four putative transcription factor binding sites of this upstream sequence were individually mutated, the resulting sequences directed different spatiotemporal expression from the same set of two core promoters, indicating that combinations of upstream factors may determine core promoter usage in sea urchin embryos. In addition, the insertion or deletion of consensus or nonconsensus TATA sequences changed the expression profile significantly, irrespective of whether the upstream sequence was intact or mutated. Thus, the TATA sequence may serve as a primary determinant for core promoter selection in these cells.

Generating imaginal disc clones in Drosophila.

Abstract: INTRODUCTIONImaginal disc primordia appear in Drosophila embryos as clusters of cells that invaginate from the embryonic epithelium. During metamorphosis, the imaginal discs form much of the outer covering of the developing adult. Generation of genetic mosaics is useful for removing or adding gene function to imaginal cells. Mitotic recombinants can be generated in a small percentage of disc cells at any stage; each cell then divides normally, forming a clone of genetically altered tissue. Mitotic recombination is induced between homologous chromosomes to generate homozygotic cells in heterozygotic flies. This is done either by irradiating heterozygotic larvae, or by using heat-shock-induced expression of flippase recombinase (FLPase) to induce recombination between FLPase recombination targets (FRTs) inserted into selected chromosome arms. In the FLPout technique, heat-shock-induced expression of FLPase joins a ubiquitous promoter to a selected coding sequence by removing blocking DNA flanked by FRTs. This technique can be used with an upstream activation sequence (UAS)-GAL4. A GAL4 FLPout clone expresses GAL4, which in turn drives the expression of any gene coupled to the UAS promoter. This protocol describes methods for generating such mosaics, by which genetic changes can be limited to small groups of imaginal cells.

Triplex formation-based artificial transcription factor to regulate target gene expression.

Abstract: A triplex formation-based artificial transcription factor to recognize any upstream sequence of target genes was developed to regulate the target gene expression. The artificial transcription factor contains a single-stranded RNA to bind with duplex DNA of the upstream sequence of the target gene to form triplex, and an effecter domain, such as activation or repression domain, of transcription factor. Reporter beta-galactosidase activity in yeast was increased 1.5-2 times by introduction of the artificial transcription factor. The novel artificial transcription factor may be a useful tool to regulate the target gene expression and reveal unknown function of the target genes.

Possible presence and role of the promoter sequence for eukaryotic RNA polymerase III in bacteria.

Abstract: The bacterial repetitive sequence IS1, is a translocatable DNA segment. The internal region of IS1 acts as a cis-element to stimulate RNA synthesis from the upstream promoter. The product of the bacterial artA gene works with this cis-element to stimulate transcription. Eukaryotic genes for small RNAs and short interspersed repetitive elements (SINEs) have internal promoters, transcribed by RNA polymerase III (RNAP III). RNAP III requires the multisubunit protein factor TFIIIC in transcription initiation. TFIIIC contains the B-block binding subunit which recognizes the internal promoter. Here, I report that the eukaryotic RNAP III promoter-like sequence was found in the cis-element of bacterial IS1. Mutations in the cis-element which affect transcription were present in the RNAP III promoter-like sequence. The RNAP III promoter sequence of Alu, which is a human SINE, was cloned into Escherichia coli, and was shown to stimulate bacterial transcription like the cis-element of IS1. Furthermore, the primary structures of ArtA protein and B-block binding subunits were compared. The amino acid sequence of ArtA appeared to be similar to the N- and C-terminal regions conserved in many B-block binding subunits. Prokaryotes and eukaryotes have been thought to have inherent transcription machineries. The results shown here, however, suggest a new aspect of the evolution of the RNAP III transcription machinery.

Nucleic acid constructs and methods of making protein

Abstract: The present invention relates to methods for producing a polypeptide, comprising: (a) cultivating a fungal host cell in a medium conducive for the production of the polypeptide, wherein the fungal host cell comprises a first polynucleotide comprising a nucleic acid sequence encoding the polypeptide operably linked to a copper-inducible promoter sequence comprising a copper-responsive upstream activation sequence activated by a copper-dependent trans-acting transcription factor and a second polynucleotide comprising one or more (several) additional copper-responsive upstream activation sequences operably linked upstream to the promoter sequence, wherein the promoter sequence is foreign to the nucleic acid sequence encoding the polypeptide and the copper-responsive upstream activation sequences are responsible for copper-induced transcription of the promoter sequence, and a third polynucleotide comprising at least one copy of a gene encoding the copper-dependent trans-acting transcription factor; and (b) isolating the polypeptide from the cultivation medium.