Project description:The CREB family of transcription factors stimulates cellular gene expression following phosphorylation at a conserved serine (Ser133 in CREB1) in response to cAMP and other extracellular signals. In order to characterize CREB target genes in various tissues, we give a cAMP agonist, forskolin (FSK), to cell lines or primary cultures and monitor the gene expression. To eliminate CREB-independent effects of FSK on cellular gene expression, we employed a dominant negative form of CREB called A-CREB, which dimerizes selectively with and blocks the DNA binding activity of CREB but not other bZIP family members. Therefore, genes that are induced by cAMP and the induction was blocked by A-CREB treatment likely represents CREB target genes. Notes: 1) In HEK293T cells, besides the Control+FSK+(FSK-ACREB) experiments, a different set of experiments showing FSK effect on 1hr and 4hr is included. The two sets of data in HEK293T were generated at different times with different batch of cells, and comparison should be limited within each set. The cAMP induced genes at 1hr, however, was similar between the two sets. 2) These is no ACREB data for pancreatic islets or hepatocytes. For hepatocytes, however, we have included fasting liver and refed liver in additional to FSK treated primary hepatocytes. During fasting, glucagon induces cAMP increase in the liver and CREB is activated. Therefore, a more reliable list of CREB target genes in hepatocytes can be obtained by selecting those genes are that induced both during fasting and in FSK treated primary culture. Keywords: parallel sample
Project description:The CREB family of transcription factors stimulates cellular gene expression following phosphorylation at a conserved serine (Ser133 in CREB1) in response to cAMP and other extracellular signals. In order to characterize CREB target genes in various tissues, we give a cAMP agonist, forskolin (FSK), to cell lines or primary cultures and monitor the gene expression. To eliminate CREB-independent effects of FSK on cellular gene expression, we employed a dominant negative form of CREB called A-CREB, which dimerizes selectively with and blocks the DNA binding activity of CREB but not other bZIP family members. Therefore, genes that are induced by cAMP and the induction was blocked by A-CREB treatment likely represents CREB target genes. Notes:; 1) In HEK293T cells, besides the Control+FSK+(FSK-ACREB) experiments, a different set of experiments showing FSK effect on 1hr and 4hr is included. The two sets of data in HEK293T were generated at different times with different batch of cells, and comparison should be limited within each set. The cAMP induced genes at 1hr, however, was similar between the two sets. 2) These is no ACREB data for pancreatic islets or hepatocytes. For hepatocytes, however, we have included fasting liver and refed liver in additional to FSK treated primary hepatocytes. During fasting, glucagon induces cAMP increase in the liver and CREB is activated. Therefore, a more reliable list of CREB target genes in hepatocytes can be obtained by selecting those genes are that induced both during fasting and in FSK treated primary culture.
Project description:Hormones and nutrients often induce genetic programs via signaling pathways that interface with gene-specific activators. Activation of the cAMP pathway, for example, stimulates cellular gene expression by means of the PKA-mediated phosphorylation of cAMP-response element binding protein (CREB) at Ser-133. Here, we use genome-wide approaches to characterize target genes that are regulated by CREB in different cellular contexts. CREB was found to occupy approximately 4,000 promoter sites in vivo, depending on the presence and methylation state of consensus cAMP response elements near the promoter. The profiles for CREB occupancy were very similar in different human tissues, and exposure to a cAMP agonist stimulated CREB phosphorylation over a majority of these sites. Only a small proportion of CREB target genes was induced by cAMP in any cell type, however, due in part to the preferential recruitment of the coactivator CREB-binding protein to those promoters. These results indicate that CREB phosphorylation alone is not a reliable predictor of target gene activation and that additional CREB regulatory partners are required for recruitment of the transcriptional apparatus to the promoter.
Project description:Transcriptome profiling of astrocyte cultures treated with forskolin (FSK), noradrenaline (NE) or infected with adenovirus carrying a constitutively active form of CREB (VP16-CREB) vs. untreated or infected with null virus. Goal is to characterize the transcriptional programs elicited by CREB activation in astrocytes.
Project description:Transcription factors (TFs) play crucial roles in kidney development and disease by recognizing specific DNA sequences to control gene expression programs. The kidney’s cellular heterogeneity poses substantial challenges to identifying the genomic binding sites and direct target genes of TFs in vivo. We apply the CUT&RUN (cleavage under targets and release using nuclease) technique, together with transcriptomic analysis, to identify cAMP-response element-binding protein (CREB) target genes in cystic epithelial cells of autosomal dominant polycystic kidney disease (ADPKD). Our results reveal that CREB binds to and activates ribosomal biogenesis genes, and that inhibition of CREB retards cyst growth in ADPKD mouse models. Our findings demonstrate that CUT&RUN is a powerful method for genome-scale profiling and identifying direct targets of TFs from small numbers of specific kidney cells.
Project description:The aim is to identify transcripts which are differentially regulated upon the duxycline-controlled induction of a transcription factor, CREB-H.<br>A cell line was developed 293.CREB-H which contains this factor under th etight control of a doxycline rwgukated activator suhc that after doxycline treatment, CREB-H is induced, and then this factor will act upon cellular target genes. These will be identiifed by comparing the profile in th esame cells before and after doxycline treatment<br>
Project description:Regulation of gene expression is essential for normal development and cellular growth. Transcriptional events are tightly controlled both spatially and temporally by specific DNA-protein interactions. In this study we finely map the genome-wide targets of the CREB protein across all known and predicted human promoters, and characterize the functional consequences of a subset of these binding events using high-throughput reporter assays. To measure CREB binding, we used HaloCHIP, an antibody-free alternative to the ChIP method that utilizes the HaloTag fusion protein, and also high-throughput promoter-luciferase reporter assays, which provide rapid and quantitative screening of promoters for transcriptional activation or repression in living cells. CREB ChIP-chip two biologcal replicates. HaloCHIP-chip three biological replicates with and without Forskolin
Project description:Transcription factors (TFs) play crucial roles in kidney development and disease by recognizing specific DNA sequences to control gene expression programs. The kidney’s cellular heterogeneity poses substantial challenges to identifying the genomic binding sites and direct target genes of TFs in vivo. We apply the CUT&RUN (cleavage under targets and release using nuclease) technique, together with transcriptomic analysis, to identify cAMP-response element-binding protein (CREB) target genes in cystic epithelial cells of autosomal dominant polycystic kidney disease (ADPKD). Our results reveal that CREB binds to and activates ribosomal biogenesis genes, and that inhibition of CREB retards cyst growth in ADPKD mouse models. Our findings demonstrate that CUT&RUN is a powerful method for genome-scale profiling and identifying direct targets of TFs from small numbers of specific kidney cells.
Project description:Background. The cAMP Response Element Binding Protein, CREB, is a transcription factor that regulates cell proliferation, differentiation, and survival in several model systems, including neuronal and hematopoietic cells. We demonstrated that CREB is overexpressed in acute myeloid and leukemia cells compared to normal hematopoietic stem cells. CREB knockdown inhibits leukemic cell proliferation in vitro and in vivo, but does not affect long-term hematopoietic reconstitution. Therefore, we propose CREB to be a potential target for therapy. To understand downstream pathways regulating CREB, we performed expression profiling with RNA from the K562 myeloid leukemia cell line. Results. By combining our expression data from CREB knockdown cells with prior ChIP data on CREB binding we were able to identify a list of putative CREB regulated genes. We performed extensive analyses on the top genes in this list as high confidence CREB targets. We found that this list is enriched for genes involved in cancer, and unexpectedly, highly enriched for histone genes. Furthermore, histone genes regulated by CREB were more likely to be specifically expressed in hematopoietic lineages. The transcription factor Elk-1 was upregulated in response to CREB deletion. Conclusions. We have identified a high confidence list of CREB targets in K562 cells. These genes allow us to begin to understand the mechanisms by which CREB contributes to acute leukemia. In particular, we speculate that the regulation of histone genes may play an important role in this process, by possibly altering the regulation of DNA replication during the cell cycle.
Project description:Regulation of gene expression is essential for normal development and cellular growth. Transcriptional events are tightly controlled both spatially and temporally by specific DNA-protein interactions. In this study we finely map the genome-wide targets of the CREB protein across all known and predicted human promoters, and characterize the functional consequences of a subset of these binding events using high-throughput reporter assays. To measure CREB binding, we used HaloCHIP, an antibody-free alternative to the ChIP method that utilizes the HaloTag fusion protein, and also high-throughput promoter-luciferase reporter assays, which provide rapid and quantitative screening of promoters for transcriptional activation or repression in living cells.