1
|
Dollinger R, Deng EB, Schultz J, Wu S, Deorio HR, Gilmour DS. Assessment of the roles of Spt5-nucleic acid contacts in promoter proximal pausing of RNA polymerase II. J Biol Chem 2023; 299:105106. [PMID: 37517697 PMCID: PMC10482750 DOI: 10.1016/j.jbc.2023.105106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 08/01/2023] Open
Abstract
Promoter proximal pausing of RNA polymerase II (Pol II) is a critical transcriptional regulatory mechanism in metazoans that requires the transcription factor DRB sensitivity-inducing factor (DSIF) and the inhibitory negative elongation factor (NELF). DSIF, composed of Spt4 and Spt5, establishes the pause by recruiting NELF to the elongation complex. However, the role of DSIF in pausing beyond NELF recruitment remains unclear. We used a highly purified in vitro system and Drosophila nuclear extract to investigate the role of DSIF in promoter proximal pausing. We identified two domains of Spt5, the KOW4 and NGN domains, that facilitate Pol II pausing. The KOW4 domain promotes pausing through its interaction with the nascent RNA while the NGN domain does so through a short helical motif that is in close proximity to the non-transcribed DNA template strand. Removal of this sequence in Drosophila has a male-specific dominant negative effect. The alpha-helical motif is also needed to support fly viability. We also show that the interaction between the Spt5 KOW1 domain and the upstream DNA helix is required for DSIF association with the Pol II elongation complex. Disruption of the KOW1-DNA interaction is dominant lethal in vivo. Finally, we show that the KOW2-3 domain of Spt5 mediates the recruitment of NELF to the elongation complex. In summary, our results reveal additional roles for DSIF in transcription regulation and identify specific domains important for facilitating Pol II pausing.
Collapse
Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Eilene B Deng
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Josie Schultz
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Sharon Wu
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Haley R Deorio
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA.
| |
Collapse
|
2
|
Negative Elongation Factor (NELF) Inhibits Premature Granulocytic Development in Zebrafish. Int J Mol Sci 2022; 23:ijms23073833. [PMID: 35409193 PMCID: PMC8998717 DOI: 10.3390/ijms23073833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 12/10/2022] Open
Abstract
Gene expression is tightly regulated during hematopoiesis. Recent studies have suggested that RNA polymerase II (Pol II) promoter proximal pausing, a temporary stalling downstream of the promoter region after initiation, plays a critical role in regulating the expression of various genes in metazoans. However, the function of proximal pausing in hematopoietic gene regulation remains largely unknown. The negative elongation factor (NELF) complex is a key factor important for this proximal pausing. Previous studies have suggested that NELF regulates granulocytic differentiation in vitro, but its in vivo function during hematopoiesis remains uncharacterized. Here, we generated the zebrafish mutant for one NELF complex subunit Nelfb using the CRISPR-Cas9 technology. We found that the loss of nelfb selectively induced excessive granulocytic development during primitive and definitive hematopoiesis. The loss of nelfb reduced hematopoietic progenitor cell formation and did not affect erythroid development. Moreover, the accelerated granulocytic differentiation and reduced progenitor cell development could be reversed by inhibiting Pol II elongation. Further experiments demonstrated that the other NELF complex subunits (Nelfa and Nelfe) played similar roles in controlling granulocytic development. Together, our studies suggested that NELF is critical in controlling the proper granulocytic development in vivo, and that promoter proximal pausing might help maintain the undifferentiated state of hematopoietic progenitor cells.
Collapse
|
3
|
Epithelial NELF guards intestinal barrier function to ameliorate colitis by maintaining junctional integrity. Mucosal Immunol 2022; 15:279-288. [PMID: 34697434 PMCID: PMC8881342 DOI: 10.1038/s41385-021-00465-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 09/27/2021] [Accepted: 10/09/2021] [Indexed: 02/04/2023]
Abstract
Well-orchestrated transcriptional programs in intestinal epithelial cells (IECs) are essential for maintenance of optimal mucosal barrier functions, whereas the contribution of elongation-related mechanisms to barrier function remains unknown. Here, a combination of genetic and genomic approaches defined a critical role of IEC-intrinsic negative elongation factor (NELF) complex in maintenance of epithelial homeostasis. By direct occupancy at endogenous gene loci, NELF sustained expression of a subset of genes related to junctional integrity. As a result, epithelial NELF deficiency results in subdued levels of these junction-related genes and excessive IEC necroptosis in vivo secondary to commensal microbial invasion. In a colitis model, NELF-deficient mice exhibited severely impaired barrier integrity characterized by increased intestinal permeability and significantly exacerbated intestinal inflammation with lethal consequences. Our findings reveal the protective function of the NELF complex against intestinal damage and inflammation and suggest that elongation represents a biologically important step in defining IEC transcriptome.
Collapse
|
4
|
Prazak L, Iwasaki Y, Kim AR, Kozlov K, King K, Gergen JP. A dual role for DNA binding by Runt in activation and repression of sloppy paired transcription. Mol Biol Cell 2021; 32:ar26. [PMID: 34432496 PMCID: PMC8693977 DOI: 10.1091/mbc.e20-08-0509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This work investigates the role of DNA binding by Runt in regulating the sloppy paired 1 (slp1) gene and in particular two distinct cis-regulatory elements that mediate regulation by Runt and other pair-rule transcription factors during Drosophila segmentation. We find that a DNA-binding-defective form of Runt is ineffective at repressing both the distal (DESE) and proximal (PESE) early stripe elements of slp1 and is also compromised for DESE-dependent activation. The function of Runt-binding sites in DESE is further investigated using site-specific transgenesis and quantitative imaging techniques. When DESE is tested as an autonomous enhancer, mutagenesis of the Runt sites results in a clear loss of Runt-dependent repression but has little to no effect on Runt-dependent activation. Notably, mutagenesis of these same sites in the context of a reporter gene construct that also contains the PESE enhancer results in a significant reduction of DESE-dependent activation as well as the loss of repression observed for the autonomous mutant DESE enhancer. These results provide strong evidence that DNA binding by Runt directly contributes to the regulatory interplay of interactions between these two enhancers in the early embryo.
Collapse
Affiliation(s)
- Lisa Prazak
- Department of Biology, Farmingdale State College, Farmingdale, NY 11735-1021.,Department of Biochemistry and Cell Biology and Center for Developmental Genetics.,Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics
| | - Ah-Ram Kim
- Graduate Program in Biochemistry and Structural Biology, and
| | - Konstantin Kozlov
- Department of Applied Mathematics, St. Petersburg State Polytechnical University, St. Petersburg, Russia 195251
| | - Kevin King
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics.,Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - J Peter Gergen
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics
| |
Collapse
|
5
|
Dollinger R, Gilmour DS. Regulation of Promoter Proximal Pausing of RNA Polymerase II in Metazoans. J Mol Biol 2021; 433:166897. [PMID: 33640324 DOI: 10.1016/j.jmb.2021.166897] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
Collapse
Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 462 North Frear, University Park, PA 16802, USA.
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 465A North Frear, University Park, PA 16802, USA.
| |
Collapse
|
6
|
Negative elongation factor complex enables macrophage inflammatory responses by controlling anti-inflammatory gene expression. Nat Commun 2020; 11:2286. [PMID: 32385332 PMCID: PMC7210294 DOI: 10.1038/s41467-020-16209-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 04/21/2020] [Indexed: 01/06/2023] Open
Abstract
Studies on macrophage gene expression have historically focused on events leading to RNA polymerase II recruitment and transcription initiation, whereas the contribution of post-initiation steps to macrophage activation remains poorly understood. Here, we report that widespread promoter-proximal RNA polymerase II pausing in resting macrophages is marked by co-localization of the negative elongation factor (NELF) complex and facilitated by PU.1. Upon inflammatory stimulation, over 60% of activated transcriptome is regulated by polymerase pause-release and a transient genome-wide NELF dissociation from chromatin, unexpectedly, independent of CDK9, a presumed NELF kinase. Genetic disruption of NELF in macrophages enhanced transcription of AP-1-encoding Fos and Jun and, consequently, AP-1 targets including Il10. Augmented expression of IL-10, a critical anti-inflammatory cytokine, in turn, attenuated production of pro-inflammatory mediators and, ultimately, macrophage-mediated inflammation in vivo. Together, these findings establish a previously unappreciated role of NELF in constraining transcription of inflammation inhibitors thereby enabling inflammatory macrophage activation. Macrophage activation is integral to innate immunity and inflammation, and involves transcriptome remodeling leading to the rapid upregulation of pro- and anti-inflammatory effector genes. Here the authors show that the negative elongation factor (NELF) complex controls the transcription of anti-inflammatory genes through Pol II pause release.
Collapse
|
7
|
Bell K, Skier K, Chen KH, Gergen JP. Two pair-rule responsive enhancers regulate wingless transcription in the Drosophila blastoderm embryo. Dev Dyn 2019; 249:556-572. [PMID: 31837063 DOI: 10.1002/dvdy.142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND While many developmentally relevant enhancers act in a modular fashion, there is growing evidence for nonadditive interactions between distinct cis-regulatory enhancers. We investigated if nonautonomous enhancer interactions underlie transcription regulation of the Drosophila segment polarity gene, wingless. RESULTS We identified two wg enhancers active at the blastoderm stage: wg 3613u, located from -3.6 to -1.3 kb upstream of the wg transcription start site (TSS) and 3046d, located in intron two of the wg gene, from 3.0 to 4.6 kb downstream of the TSS. Genetic experiments confirm that Even Skipped (Eve), Fushi-tarazu (Ftz), Runt, Odd-paired (Opa), Odd-skipped (Odd), and Paired (Prd) contribute to spatially regulated wg expression. Interestingly, there are enhancer specific differences in response to the gain or loss of function of pair-rule gene activity. Although each element recapitulates aspects of wg expression, a composite reporter containing both enhancers more faithfully recapitulates wg regulation than would be predicted from the sum of their individual responses. CONCLUSION These results suggest that the regulation of wg by pair-rule genes involves nonadditive interactions between distinct cis-regulatory enhancers.
Collapse
Affiliation(s)
- Kimberly Bell
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York
- Center for Excellence in Learning & Teaching, Stony Brook University, Stony Brook, New York
| | - Kevin Skier
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Kevin H Chen
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York
- Boston University School of Medicine, Boston, Massachusetts
| | - John Peter Gergen
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York
| |
Collapse
|
8
|
Yang H, Basquin D, Pauli D, Oliver B. Drosophila melanogaster positive transcriptional elongation factors regulate metabolic and sex-biased expression in adults. BMC Genomics 2017; 18:384. [PMID: 28521739 PMCID: PMC5436443 DOI: 10.1186/s12864-017-3755-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/03/2017] [Indexed: 11/22/2022] Open
Abstract
Background Transcriptional elongation is a generic function, but is also regulated to allow rapid transcription responses. Following relatively long initiation and promoter clearance, RNA polymerase II can pause and then rapidly elongate following recruitment of positive elongation factors. Multiple elongation complexes exist, but the role of specific components in adult Drosophila is underexplored. Results We conducted RNA-seq experiments to analyze the effect of RNAi knockdown of Suppressor of Triplolethal and lilliputian. We similarly analyzed the effect of expressing a dominant negative Cyclin-dependent kinase 9 allele. We observed that almost half of the genes expressed in adults showed reduced expression, supporting a broad role for the three tested genes in steady-state transcript abundance. Expression profiles following lilliputian and Suppressor of Triplolethal RNAi were nearly identical raising the possibility that they are obligatory co-factors. Genes showing reduced expression due to these RNAi treatments were short and enriched for genes encoding metabolic or enzymatic functions. The dominant-negative Cyclin-dependent kinase 9 profiles showed both overlapping and specific differential expression, suggesting involvement in multiple complexes. We also observed hundreds of genes with sex-biased differential expression following treatment. Conclusion Transcriptional profiles suggest that Lilliputian and Suppressor of Triplolethal are obligatory cofactors in the adult and that they can also function with Cyclin-dependent kinase 9 at a subset of loci. Our results suggest that transcriptional elongation control is especially important for rapidly expressed genes to support digestion and metabolism, many of which have sex-biased function. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3755-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Haiwang Yang
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA.
| | - Denis Basquin
- Department of Genetics & Evolution, Sciences III, University of Geneva, Boulevard d'Yvoy 4, CH 1205, Geneva, Switzerland
| | - Daniel Pauli
- Department of Genetics & Evolution, Sciences III, University of Geneva, Boulevard d'Yvoy 4, CH 1205, Geneva, Switzerland
| | - Brian Oliver
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA
| |
Collapse
|
9
|
Mendoza-García P, Hugosson F, Fallah M, Higgins ML, Iwasaki Y, Pfeifer K, Wolfstetter G, Varshney G, Popichenko D, Gergen JP, Hens K, Deplancke B, Palmer RH. The Zic family homologue Odd-paired regulates Alk expression in Drosophila. PLoS Genet 2017; 13:e1006617. [PMID: 28369060 PMCID: PMC5393633 DOI: 10.1371/journal.pgen.1006617] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 04/17/2017] [Accepted: 02/07/2017] [Indexed: 01/30/2023] Open
Abstract
The Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) plays a critical role in the specification of founder cells (FCs) in the Drosophila visceral mesoderm (VM) during embryogenesis. Reporter gene and CRISPR/Cas9 deletion analysis reveals enhancer regions in and upstream of the Alk locus that influence tissue-specific expression in the amnioserosa (AS), the VM and the epidermis. By performing high throughput yeast one-hybrid screens (Y1H) with a library of Drosophila transcription factors (TFs) we identify Odd-paired (Opa), the Drosophila homologue of the vertebrate Zic family of TFs, as a novel regulator of embryonic Alk expression. Further characterization identifies evolutionarily conserved Opa-binding cis-regulatory motifs in one of the Alk associated enhancer elements. Employing Alk reporter lines as well as CRISPR/Cas9-mediated removal of regulatory elements in the Alk locus, we show modulation of Alk expression by Opa in the embryonic AS, epidermis and VM. In addition, we identify enhancer elements that integrate input from additional TFs, such as Binou (Bin) and Bagpipe (Bap), to regulate VM expression of Alk in a combinatorial manner. Taken together, our data show that the Opa zinc finger TF is a novel regulator of embryonic Alk expression. The Alk receptor tyrosine kinase is employed repeatedly during Drosophila development to drive signaling events in a variety of tissues. The spatial and temporal expression pattern of the Alk gene is tightly regulated. Identifying factors that influence the expression of Alk is important to better understand how Alk signaling is controlled. In this paper we characterize cis-regulatory sequences in the Alk locus and the transcription factors that bind them to govern Alk expression in the Drosophila embryo. Using a robotic protein-DNA interaction assay, we identified the Zic family transcription factor Odd-paired as a factor that binds to regulatory elements in the Alk locus. Binding of Odd-paired to Alkcis-regulatory elements varies spatially, revealing a requirement for additional transcription factors such as the NK3 and FoxF orthologues Bagpipe and Biniou in a subset of Alk-expressing tissues. Our findings provide new insight into the dynamics underlying temporal and spatial regulation of the Alk receptor during embryogenesis.
Collapse
Affiliation(s)
- Patricia Mendoza-García
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Fredrik Hugosson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mahsa Fallah
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Michael L. Higgins
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Kathrin Pfeifer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Georg Wolfstetter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gaurav Varshney
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - J. Peter Gergen
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Korneel Hens
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Bart Deplancke
- Laboratory of Systems Biology and Genetics, Lausanne, Switzerland
| | - Ruth H. Palmer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
| |
Collapse
|
10
|
Hang S, Gergen JP. Different modes of enhancer-specific regulation by Runt and Even-skipped during Drosophila segmentation. Mol Biol Cell 2017; 28:681-691. [PMID: 28077616 PMCID: PMC5328626 DOI: 10.1091/mbc.e16-09-0630] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/13/2016] [Accepted: 01/04/2017] [Indexed: 12/04/2022] Open
Abstract
Expression of the Drosophila slp1 gene depends on nonadditive interactions between two cis-regulatory enhancers. These enhancers are repressed by preventing either Pol II recruitment or release of promoter-proximal paused Pol II in a manner that is both enhancer and transcription factor specific and can account for their nonadditive interaction. The initial metameric expression of the Drosophila sloppy paired 1 (slp1) gene is controlled by two distinct cis-regulatory DNA elements that interact in a nonadditive manner to integrate inputs from transcription factors encoded by the pair-rule segmentation genes. We performed chromatin immunoprecipitation on reporter genes containing these elements in different embryonic genotypes to investigate the mechanism of their regulation. The distal early stripe element (DESE) mediates both activation and repression by Runt. We find that the differential response of DESE to Runt is due to an inhibitory effect of Fushi tarazu (Ftz) on P-TEFb recruitment and the regulation of RNA polymerase II (Pol II) pausing. The proximal early stripe element (PESE) is also repressed by Runt, but in this case, Runt prevents PESE-dependent Pol II recruitment and preinitiation complex (PIC) assembly. PESE is also repressed by Even-skipped (Eve), but, of interest, this repression involves regulation of P-TEFb recruitment and promoter-proximal Pol II pausing. These results demonstrate that the mode of slp1 repression by Runt is enhancer specific, whereas the mode of repression of the slp1 PESE enhancer is transcription factor specific. We propose a model based on these differential regulatory interactions that accounts for the nonadditive interactions between the PESE and DESE enhancers during Drosophila segmentation.
Collapse
Affiliation(s)
- Saiyu Hang
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics and.,Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, NY 11794
| | - J Peter Gergen
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics and
| |
Collapse
|
11
|
Kok K, Ay A, Li LM, Arnosti DN. Genome-wide errant targeting by Hairy. eLife 2015; 4. [PMID: 26305409 PMCID: PMC4547095 DOI: 10.7554/elife.06394] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 07/24/2015] [Indexed: 01/08/2023] Open
Abstract
Metazoan transcriptional repressors regulate chromatin through diverse histone modifications. Contributions of individual factors to the chromatin landscape in development is difficult to establish, as global surveys reflect multiple changes in regulators. Therefore, we studied the conserved Hairy/Enhancer of Split family repressor Hairy, analyzing histone marks and gene expression in Drosophila embryos. This long-range repressor mediates histone acetylation and methylation in large blocks, with highly context-specific effects on target genes. Most strikingly, Hairy exhibits biochemical activity on many loci that are uncoupled to changes in gene expression. Rather than representing inert binding sites, as suggested for many eukaryotic factors, many regions are targeted errantly by Hairy to modify the chromatin landscape. Our findings emphasize that identification of active cis-regulatory elements must extend beyond the survey of prototypical chromatin marks. We speculate that this errant activity may provide a path for creation of new regulatory elements, facilitating the evolution of novel transcriptional circuits.
Collapse
Affiliation(s)
- Kurtulus Kok
- Genetics Program, Michigan State University, East Lansing, United States
| | - Ahmet Ay
- Departments of Biology and Mathematics, Colgate University, Hamilton, United States
| | - Li M Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - David N Arnosti
- Genetics Program, Michigan State University, East Lansing, United States
| |
Collapse
|
12
|
Rao MK, Matsumoto Y, Richardson ME, Panneerdoss S, Bhardwaj A, Ward JM, Shanker S, Bettegowda A, Wilkinson MF. Hormone-induced and DNA demethylation-induced relief of a tissue-specific and developmentally regulated block in transcriptional elongation. J Biol Chem 2014; 289:35087-101. [PMID: 25331959 DOI: 10.1074/jbc.m114.615435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Genome-wide studies have revealed that genes commonly have a high density of RNA polymerase II just downstream of the transcription start site. This has raised the possibility that genes are commonly regulated by transcriptional elongation, but this remains largely untested in vivo, particularly in vertebrates. Here, we show that the proximal promoter from the Rhox5 homeobox gene recruits polymerase II and begins elongating in all tissues and cell lines that we tested, but it only completes elongation in a tissue-specific and developmentally regulated manner. Relief of the elongation block is associated with recruitment of the elongation factor P-TEFb, the co-activator GRIP1, the chromatin remodeling factor BRG1, and specific histone modifications. We provide evidence that two mechanisms relieve the elongation block at the proximal promoter: demethylation and recruitment of androgen receptor. Together, our findings support a model in which promoter proximal pausing helps confer tissue-specific and developmental gene expression through a mechanism regulated by DNA demethylation-dependent nuclear hormone receptor recruitment.
Collapse
Affiliation(s)
- Manjeet K Rao
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Greehey Children's Cancer Research Institute, Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Yuiko Matsumoto
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Marcy E Richardson
- the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Subbarayalu Panneerdoss
- the Greehey Children's Cancer Research Institute, Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Anjana Bhardwaj
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Jacqueline M Ward
- the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Sreenath Shanker
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Anilkumar Bettegowda
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Miles F Wilkinson
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| |
Collapse
|
13
|
Han L, Vickers KC, Samuels DC, Guo Y. Alternative applications for distinct RNA sequencing strategies. Brief Bioinform 2014; 16:629-39. [PMID: 25246237 DOI: 10.1093/bib/bbu032] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/19/2014] [Indexed: 12/30/2022] Open
Abstract
Recent advances in RNA library preparation methods, platform accessibility and cost efficiency have allowed high-throughput RNA sequencing (RNAseq) to replace conventional hybridization microarray platforms as the method of choice for mRNA profiling and transcriptome analyses. RNAseq is a powerful technique to profile both long and short RNA expression, and the depth of information gained from distinct RNAseq methods is striking and facilitates discovery. In addition to expression analysis, distinct RNAseq approaches also allow investigators the ability to assess transcriptional elongation, DNA variance and exogenous RNA content. Here we review the current state of the art in transcriptome sequencing and address epigenetic regulation, quantification of transcription activation, RNAseq output and a diverse set of applications for RNAseq data. We detail how RNAseq can be used to identify allele-specific expression, single-nucleotide polymorphisms and somatic mutations and discuss the benefits and limitations of using RNAseq to monitor DNA characteristics. Moreover, we highlight the power of combining RNA- and DNAseq methods for genomic analysis. In summary, RNAseq provides the opportunity to gain greater insight into transcriptional regulation and output than simply miRNA and mRNA profiling.
Collapse
|
14
|
Abstract
The study of long noncoding RNAs (lncRNAs) is still in its infancy with more putative RNAs identified than those with ascribed functions. Defined as transcripts that are longer than 200 nucleotides without a coding sequence, their numbers are on the rise and may well challenge protein coding transcripts in number and diversity. lncRNAs are often expressed at low levels and their sequences are frequently poorly conserved, making it unclear if they are transcriptional noise or bonafide effectors. Despite these limitations, inroads into their functions are being made and it is clear they make a contribution in regulating all aspects of biology. The early verdict on their activity, however, suggests the majority function as chromatin modifiers. A good proportion show a connection to disease highlighting their importance and the need to determine their function. The focus of this review is on lncRNAs which influence developmental processes which in itself covers a large range of known activities.
Collapse
Affiliation(s)
- Jamila I Horabin
- Department of Biomedical Sciences, College of Medicine, Florida State University, Rm 3300-G, 1115 W. Call St., Tallahassee, FL, 32306-4300, USA,
| |
Collapse
|
15
|
Saunders A, Core LJ, Sutcliffe C, Lis JT, Ashe HL. Extensive polymerase pausing during Drosophila axis patterning enables high-level and pliable transcription. Genes Dev 2013; 27:1146-58. [PMID: 23699410 DOI: 10.1101/gad.215459.113] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cascades of zygotic gene expression pattern the anterior-posterior (AP) and dorsal-ventral (DV) axes of the early Drosophila embryo. Here, we used the global run-on sequencing assay (GRO-seq) to map the genome-wide RNA polymerase distribution during early Drosophila embryogenesis, thus providing insights into how genes are regulated. We identify widespread promoter-proximal pausing yet show that the presence of paused polymerase does not necessarily equate to direct regulation through pause release to productive elongation. Our data reveal that a subset of early Zelda-activated genes is regulated at the level of polymerase recruitment, whereas other Zelda target and axis patterning genes are predominantly regulated through pause release. In contrast to other signaling pathways, we found that bone morphogenetic protein (BMP) target genes are collectively more highly paused than BMP pathway components and show that BMP target gene expression requires the pause-inducing negative elongation factor (NELF) complex. Our data also suggest that polymerase pausing allows plasticity in gene activation throughout embryogenesis, as transiently repressed and transcriptionally silenced genes maintain and lose promoter polymerases, respectively. Finally, we provide evidence that the major effect of pausing is on the levels, rather than timing, of transcription. These data are discussed in terms of the efficiency of transcriptional activation required across cell populations during developmental time constraints.
Collapse
Affiliation(s)
- Abbie Saunders
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | | | | | | | | |
Collapse
|
16
|
Xu J, Grant G, Sabin LR, Gordesky-Gold B, Yasunaga A, Tudor M, Cherry S. Transcriptional pausing controls a rapid antiviral innate immune response in Drosophila. Cell Host Microbe 2013; 12:531-43. [PMID: 23084920 DOI: 10.1016/j.chom.2012.08.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/27/2012] [Accepted: 08/31/2012] [Indexed: 12/21/2022]
Abstract
Innate immune responses are characterized by precise gene expression whereby gene subsets are temporally induced to limit infection, although the mechanisms involved are incompletely understood. We show that antiviral immunity in Drosophila requires the transcriptional pausing pathway, including negative elongation factor (NELF) that pauses RNA polymerase II (Pol II) and positive elongation factor b (P-TEFb), which releases paused Pol II to produce full-length transcripts. We identify a set of genes that is rapidly transcribed upon arbovirus infection, including components of antiviral pathways (RNA silencing, autophagy, JAK/STAT, Toll, and Imd) and various Toll receptors. Many of these genes require P-TEFb for expression and exhibit pausing-associated chromatin features. Furthermore, transcriptional pausing is critical for antiviral immunity in insects because NELF and P-TEFb are required to restrict viral replication in adult flies and vector mosquito cells. Thus, transcriptional pausing primes virally induced genes to facilitate rapid gene induction and robust antiviral responses.
Collapse
Affiliation(s)
- Jie Xu
- Department of Microbiology, Penn Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19146, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
Castelo-Branco G, Amaral PP, Engström PG, Robson SC, Marques SC, Bertone P, Kouzarides T. The non-coding snRNA 7SK controls transcriptional termination, poising, and bidirectionality in embryonic stem cells. Genome Biol 2013; 14:R98. [PMID: 24044525 PMCID: PMC4053805 DOI: 10.1186/gb-2013-14-9-r98] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pluripotency is characterized by a unique transcriptional state, in which lineage-specification genes are poised for transcription upon exposure to appropriate stimuli, via a bivalency mechanism involving the simultaneous presence of activating and repressive methylation marks at promoter-associated histones. Recent evidence suggests that other mechanisms, such as RNA polymerase II pausing, might be operational in this process, but their regulation remains poorly understood. RESULTS Here we identify the non-coding snRNA 7SK as a multifaceted regulator of transcription in embryonic stem cells. We find that 7SK represses a specific cohort of transcriptionally poised genes with bivalent or activating chromatin marks in these cells, suggesting a novel poising mechanism independent of Polycomb activity. Genome-wide analysis shows that 7SK also prevents transcription downstream of polyadenylation sites at several active genes, indicating that 7SK is required for normal transcriptional termination or control of 3′-UTR length. In addition, 7SK suppresses divergent upstream antisense transcription at more than 2,600 loci, including many that encode divergent long non-coding RNAs, a finding that implicates the 7SK snRNA in the control of transcriptional bidirectionality. CONCLUSIONS Our study indicates that a single non-coding RNA, the snRNA 7SK, is a gatekeeper of transcriptional termination and bidirectional transcription in embryonic stem cells and mediates transcriptional poising through a mechanism independent of chromatin bivalency.
Collapse
Affiliation(s)
- Gonçalo Castelo-Branco
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet,SE-17177 Stockholm, Sweden
| | - Paulo P Amaral
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Pär G Engström
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
- Present address: Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Box 1031, SE-17121 Solna, Sweden
| | - Samuel C Robson
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Sueli C Marques
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet,SE-17177 Stockholm, Sweden
| | - Paul Bertone
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
- Genome Biology and Developmental Biology Units, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
- Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Tony Kouzarides
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| |
Collapse
|
18
|
Transcriptional repressors: shutting off gene expression at the source affects developmental dynamics. Curr Biol 2012; 21:R859-60. [PMID: 22032193 DOI: 10.1016/j.cub.2011.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Developmental networks feature genes interlinked by transcriptional activation and repression. A new study indicates that repressors can 'shut the door' to newly initiating polymerases, allowing longer target genes to produce latent transcripts after shorter genes have been effectively silenced.
Collapse
|
19
|
Zhao LN, Qin Z, Wei P, Guo HS, Dang XL, Wang SG, Tang B. Elongation factor 1β' gene from Spodoptera exigua: characterization and function identification through RNA interference. Int J Mol Sci 2012; 13:8126-8141. [PMID: 22942694 PMCID: PMC3430225 DOI: 10.3390/ijms13078126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 06/13/2012] [Accepted: 06/18/2012] [Indexed: 01/07/2023] Open
Abstract
Elongation factor (EF) is a key regulation factor for translation in many organisms, including plants, bacteria, fungi, animals and insects. To investigate the nature and function of elongation factor 1β′ from Spodoptera exigua (SeEF-1β′), its cDNA was cloned. This contained an open reading frame of 672 nucleotides encoding a protein of 223 amino acids with a predicted molecular weight of 24.04 kDa and pI of 4.53. Northern blotting revealed that SeEF-1β′ mRNA is expressed in brain, epidermis, fat body, midgut, Malpighian tubules, ovary and tracheae. RT-PCR revealed that SeEF-1β′ mRNA is expressed at different levels in fat body and whole body during different developmental stages. In RNAi experiments, the survival rate of insects injected with SeEF-1β′ dsRNA was 58.7% at 36 h after injection, which was significantly lower than three control groups. Other elongation factors and transcription factors were also influenced when EF-1β′ was suppressed. The results demonstrate that SeEF-1β′ is a key gene in transcription in S. exigua.
Collapse
Affiliation(s)
- Li-Na Zhao
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
| | - Zi Qin
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
| | - Ping Wei
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
| | - Hong-Shuang Guo
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
| | - Xiang-Li Dang
- Zhejiang Institute of Subtropical Crops, Wenzhou, Zhejiang 325005, China; E-Mail:
| | - Shi-Gui Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
| | - Bin Tang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; E-Mails: (L.-N.Z.); (Z.Q.); (P.W.); (H.-S.G.); (S.-G.W.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +86-571-2886-5680; Fax: +86-571-2886-5680
| |
Collapse
|
20
|
Bothma JP, Magliocco J, Levine M. The snail repressor inhibits release, not elongation, of paused Pol II in the Drosophila embryo. Curr Biol 2011; 21:1571-7. [PMID: 21920753 DOI: 10.1016/j.cub.2011.08.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 07/11/2011] [Accepted: 08/08/2011] [Indexed: 12/25/2022]
Abstract
The development of the precellular Drosophila embryo is characterized by exceptionally rapid transitions in gene activity, with broadly distributed maternal regulatory gradients giving way to precise on/off patterns of gene expression within a one-hour window, between two and three hours after fertilization [1]. Transcriptional repression plays a pivotal role in this process, delineating sharp expression patterns (e.g., pair-rule stripes) within broad domains of gene activation. As many as 20 different sequence-specific repressors have been implicated in this process, yet the mechanisms by which they silence gene expression have remained elusive [2]. Here we report the development of a method for the quantitative visualization of transcriptional repression. We focus on the Snail repressor, which establishes the boundary between the presumptive mesoderm and neurogenic ectoderm [3]. We find that elongating Pol II complexes complete transcription after the onset of Snail repression. As a result, moderately sized genes (e.g., the 22 kb sog locus) are fully silenced only after tens of minutes of repression. We propose that this "repression lag" imposes a severe constraint on the regulatory dynamics of embryonic patterning and further suggest that posttranscriptional regulators, like microRNAs, are required to inhibit unwanted transcripts produced during protracted periods of gene silencing.
Collapse
Affiliation(s)
- Jacques P Bothma
- Biophysics Graduate Group, Center for Integrative Genomics, Division of Genetics, Genomics and Development, University of California, Berkeley, Berkeley, CA 94720, USA.
| | | | | |
Collapse
|
21
|
Sun J, Pan H, Lei C, Yuan B, Nair SJ, April C, Parameswaran B, Klotzle B, Fan JB, Ruan J, Li R. Genetic and genomic analyses of RNA polymerase II-pausing factor in regulation of mammalian transcription and cell growth. J Biol Chem 2011; 286:36248-57. [PMID: 21865163 DOI: 10.1074/jbc.m111.269167] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Many mammalian genes are occupied by paused RNA polymerase II (pol II) in the promoter-proximal region on both sides of the transcription start site. However, the impact of pol II pausing on gene expression and cell biology is not fully understood. In this study, we used a Cre-Lox system to conditionally knock out the b subunit of mouse negative elongation factor (Nelf-b), a key pol II-pausing factor, in mouse embryonic fibroblasts. We found that Nelf-b was associated with the promoter-proximal region of the majority of expressed genes, yet genetic ablation of Nelf-b only affected the steady-state mRNA levels of a small percentage of the Nelf-b-associated genes. Interestingly, Nelf-b deletion also increased levels of transcription start site upstream transcripts at multiple negative elongation factor-associated genes. The direct target genes of Nelf-b were highly enriched with those involved in the control of cell growth and cell death. Correspondingly, Nelf-b knock-out mouse embryonic fibroblasts exhibited slower progression from quiescence to proliferation, as well as in a cycling cell population. Furthermore, Nelf-b deletion also resulted in increased apoptosis. Thus, the genetic and genomic studies provide new physiological and molecular insight into Nelf-mediated pol II pausing.
Collapse
Affiliation(s)
- Jianlong Sun
- Department of Molecular Medicine/Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Levine M. Paused RNA polymerase II as a developmental checkpoint. Cell 2011; 145:502-11. [PMID: 21565610 DOI: 10.1016/j.cell.2011.04.021] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/18/2011] [Accepted: 04/25/2011] [Indexed: 11/18/2022]
Abstract
The textbook view of gene activation is that the rate-limiting step is the interaction of RNA polymerase II (Pol II) with the gene's promoter. However, studies in a variety of systems, including human embryonic stem cells and the early Drosophila embryo, have begun to challenge this view. There is increasing evidence that differential gene expression often depends on the regulation of transcription elongation via the release of Pol II from the proximal promoter. I review the implications of this mechanism of gene activation with respect to the orderly unfolding of complex gene networks governing animal development.
Collapse
Affiliation(s)
- Michael Levine
- Division of Genetics, Genomics, and Development, Department of Molecular and Cell Biology, Center for Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| |
Collapse
|
23
|
Li LM, Arnosti DN. Long- and short-range transcriptional repressors induce distinct chromatin states on repressed genes. Curr Biol 2011; 21:406-12. [PMID: 21353562 DOI: 10.1016/j.cub.2011.01.054] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/19/2010] [Accepted: 01/20/2011] [Indexed: 12/25/2022]
Abstract
Transcriptional repression is essential for establishing precise patterns of gene expression during development. Repressors governing early Drosophila segmentation can be classified as short- or long-range factors based on their ranges of action, acting either locally to quench adjacent activators or broadly to silence an entire locus. Paradoxically, these repressors recruit common corepressors, Groucho and CtBP, despite their different ranges of repression. To reveal the mechanisms underlying these two distinct modes of repression, we performed chromatin analysis using the prototypical long-range repressor Hairy and the short-range repressor Knirps. Chromatin immunoprecipitation and micrococcal nuclease mapping studies reveal that Knirps causes local changes of histone density and acetylation, and the inhibition of activator recruitment, without affecting the recruitment of basal transcriptional machinery. In contrast, Hairy induces widespread histone deacetylation and inhibits the recruitment of basal machinery without inducing chromatin compaction. Our study provides detailed mechanistic insight into short- and long-range repression on selected endogenous target genes and suggests that the transcriptional corepressors can be differentially deployed to mediate chromatin changes in a context-dependent manner.
Collapse
Affiliation(s)
- Li M Li
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824-1319, USA
| | | |
Collapse
|
24
|
Walrad PB, Hang S, Gergen JP. Hairless is a cofactor for Runt-dependent transcriptional regulation. Mol Biol Cell 2011; 22:1364-74. [PMID: 21325629 PMCID: PMC3078061 DOI: 10.1091/mbc.e10-06-0483] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Runt is a vital transcriptional regulator in the developmental pathway responsible for segmentation in the Drosophila embryo. Runt activates or represses transcription in a manner that is dependent on both cellular context and the specific downstream target. Here we identify Hairless (H) as a Runt-interacting molecule that functions during segmentation. We find that H is important for maintenance of engrailed (en) repression as was previously demonstrated for Groucho (Gro), Rpd3, and CtBP. H also contributes to the Runt-dependent repression of sloppy-paired-1 (slp1), a role that is not shared with these other corepressors. We further find distinct roles for these different corepressors in the regulation of other Runt targets in the early Drosophila embryo. These findings, coupled with observations on the distinct functional requirements for Runt in regulating these several different targets, indicate that Runt-dependent regulation in the Drosophila blastoderm embryo relies on unique, target-gene-specific molecular interactions.
Collapse
Affiliation(s)
- Pegine B Walrad
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | | | | |
Collapse
|
25
|
Li J, Gilmour DS. Promoter proximal pausing and the control of gene expression. Curr Opin Genet Dev 2011; 21:231-5. [PMID: 21324670 DOI: 10.1016/j.gde.2011.01.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/18/2011] [Indexed: 12/18/2022]
Abstract
The advent of methods for mapping the location of specific proteins across genomes is substantially enlightening our understanding of gene regulation. One recent discovery is that Pol II is concentrated at the 5' end of thousands of genes in mammalian and Drosophila cells. Before this, much research had focused on understanding how sequence-specific, DNA-binding proteins orchestrate the actions of regulators of chromatin structure and the general transcriptional machinery to control transcription initiation. The concentration of Pol II at the 5' ends of genes indicates that key steps regulating transcription occur after Pol II has associated with a gene's promoter.
Collapse
Affiliation(s)
- Jian Li
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
| | | |
Collapse
|
26
|
Wang X, Hang S, Prazak L, Gergen JP. NELF potentiates gene transcription in the Drosophila embryo. PLoS One 2010; 5:e11498. [PMID: 20634899 PMCID: PMC2901382 DOI: 10.1371/journal.pone.0011498] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 06/17/2010] [Indexed: 02/06/2023] Open
Abstract
A hallmark of genes that are subject to developmental regulation of transcriptional elongation is association of the negative elongation factor NELF with the paused RNA polymerase complex. Here we use a combination of biochemical and genetic experiments to investigate the in vivo function of NELF in the Drosophila embryo. NELF associates with different gene promoter regions in correlation with the association of RNA polymerase II (Pol II) and the initial activation of gene expression during the early stages of embryogenesis. Genetic experiments reveal that maternally provided NELF is required for the activation, rather than the repression of reporter genes that emulate the expression of key developmental control genes. Furthermore, the relative requirement for NELF is dictated by attributes of the flanking cis-regulatory information. We propose that NELF-associated paused Pol II complexes provide a platform for high fidelity integration of the combinatorial spatial and temporal information that is central to the regulation of gene expression during animal development.
Collapse
Affiliation(s)
- Xiaoling Wang
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Saiyu Hang
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Lisa Prazak
- Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - J. Peter Gergen
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
| |
Collapse
|
27
|
Interactions between DSIF (DRB sensitivity inducing factor), NELF (negative elongation factor), and the Drosophila RNA polymerase II transcription elongation complex. Proc Natl Acad Sci U S A 2010; 107:11301-6. [PMID: 20534440 DOI: 10.1073/pnas.1000681107] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Negative elongation factor (NELF) and 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole sensitivity-inducing factor (DSIF) are involved in pausing RNA Polymerase II (Pol II) in the promoter-proximal region of the hsp70 gene in Drosophila, before heat shock induction. Such blocks in elongation are widespread in the Drosophila genome. However, the mechanism by which DSIF and NELF participate in setting up the paused Pol II remains unclear. We analyzed the interactions among DSIF, NELF, and a reconstituted Drosophila Pol II elongation complex to gain insight into the mechanism of pausing. Our results show that DSIF and NELF require a nascent transcript longer than 18 nt to stably associate with the Pol II elongation complex. Protein-RNA cross-linking reveals that Spt5, the largest subunit of DSIF, contacts the nascent RNA as the RNA emerges from the elongation complex. Taken together, these results provide a possible model by which DSIF binds the elongation complex via association with the nascent transcript and subsequently recruits NELF. Although DSIF and NELF were both required for inhibition of transcription, we did not detect a NELF-RNA contact when the nascent transcript was between 22 and 31 nt long, which encompasses the region where promoter-proximal pausing occurs on many genes in Drosophila. This raises the possibility that RNA binding by NELF is not necessary in promoter-proximal pausing.
Collapse
|
28
|
Patel SA, Simon MC. Functional analysis of the Cdk7.cyclin H.Mat1 complex in mouse embryonic stem cells and embryos. J Biol Chem 2010; 285:15587-15598. [PMID: 20231280 PMCID: PMC2865308 DOI: 10.1074/jbc.m109.081687] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 02/22/2010] [Indexed: 01/27/2023] Open
Abstract
The trimeric Cdk7.cyclin H.Mat1 complex functions in cell cycle regulation, as the Cdk-activating kinase, and in transcription, as a module of the general transcription factor TFIIH. As a component of TFIIH, Cdk7 phosphorylates serines 5 and 7 of the carboxyl-terminal domain of RNA polymerase II and can also directly phosphorylate transcription factors to regulate gene expression. Here we have investigated the function of the Cdk7.cyclin H.Mat1 complex in murine embryonic stem (ES) cells and preimplantation embryos to determine whether it regulates the unique cell cycle structure and transcriptional network of pluripotent cells. We demonstrate that depletion of cyclin H leads to differentiation of ES cells independent of changes in cell cycle progression. In contrast, we observed that developmental genes are acutely up-regulated after cyclin H down-regulation, likely perturbing normal ES self-renewal pathways. We further demonstrate that Spt5, a known phosphorylation target of Cdk7, similarly regulates ES pluripotency and gene expression. Consistent with its function in ES cells, cyclin H depletion from mouse embryos also leads to defects in the expansion of the inner cell mass of blastocysts, a transient pluripotent stem cell population in vivo. Our findings indicate that cyclin H has an essential function in promoting the self-renewal of the pluripotent stem cells of blastocyst stage embryos. Collectively, these studies demonstrate a critical and novel role for cyclin H in maintaining ES cell identity and suggest that cyclin H has important functions in early embryonic development.
Collapse
Affiliation(s)
- Shetal A Patel
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104; School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - M Celeste Simon
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104; School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
| |
Collapse
|
29
|
Johnson ML, Nagengast AA, Salz HK. PPS, a large multidomain protein, functions with sex-lethal to regulate alternative splicing in Drosophila. PLoS Genet 2010; 6:e1000872. [PMID: 20221253 PMCID: PMC2832672 DOI: 10.1371/journal.pgen.1000872] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 02/03/2010] [Indexed: 12/25/2022] Open
Abstract
Alternative splicing controls the expression of many genes, including the Drosophila sex determination gene Sex-lethal (Sxl). Sxl expression is controlled via a negative regulatory mechanism where inclusion of the translation-terminating male exon is blocked in females. Previous studies have shown that the mechanism leading to exon skipping is autoregulatory and requires the SXL protein to antagonize exon inclusion by interacting with core spliceosomal proteins, including the U1 snRNP protein Sans-fille (SNF). In studies begun by screening for proteins that interact with SNF, we identified PPS, a previously uncharacterized protein, as a novel component of the machinery required for Sxl male exon skipping. PPS encodes a large protein with four signature motifs, PHD, BRK, TFS2M, and SPOC, typically found in proteins involved in transcription. We demonstrate that PPS has a direct role in Sxl male exon skipping by showing first that loss of function mutations have phenotypes indicative of Sxl misregulation and second that the PPS protein forms a complex with SXL and the unspliced Sxl RNA. In addition, we mapped the recruitment of PPS, SXL, and SNF along the Sxl gene using chromatin immunoprecipitation (ChIP), which revealed that, like many other splicing factors, these proteins bind their RNA targets while in close proximity to the DNA. Interestingly, while SNF and SXL are specifically recruited to their predicted binding sites, PPS has a distinct pattern of accumulation along the Sxl gene, associating with a region that includes, but is not limited to, the SxlPm promoter. Together, these data indicate that PPS is different from other splicing factors involved in male-exon skipping and suggest, for the first time, a functional link between transcription and SXL-mediated alternative splicing. Loss of zygotic PPS function, however, is lethal to both sexes, indicating that its role may be of broad significance.
Collapse
Affiliation(s)
- Matthew L. Johnson
- Department of Genetics, Case Western Reserve University, School of Medicine, Cleveland, Ohio, United States of America
| | - Alexis A. Nagengast
- Department of Genetics, Case Western Reserve University, School of Medicine, Cleveland, Ohio, United States of America
| | - Helen K. Salz
- Department of Genetics, Case Western Reserve University, School of Medicine, Cleveland, Ohio, United States of America
| |
Collapse
|
30
|
Zeitlinger J, Stark A. Developmental gene regulation in the era of genomics. Dev Biol 2010; 339:230-9. [PMID: 20045679 DOI: 10.1016/j.ydbio.2009.12.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 12/04/2009] [Accepted: 12/23/2009] [Indexed: 01/30/2023]
Abstract
Genetic experiments over the last few decades have identified many developmental control genes critical for pattern formation and cell fate specification during the development of multicellular organisms. A large fraction of these genes encode transcription factors and signaling molecules, show highly dynamic expression patterns during development, and are deeply evolutionarily conserved and deregulated in various human diseases such as cancer. Because of their importance in development, evolution, and disease, a fundamental question in biology is how these developmental control genes are regulated in such an extensive and precise fashion. Using genomics methods, it has become clear that developmental control genes are a distinct group of genes with special regulatory characteristics. However, a systematic analysis of these characteristics has not been presented. Here we review how developmental control genes were discovered, evaluate their genome-wide regulation and gene structure, discuss emerging evidence for their mode of regulation, and estimate their overall abundance in the genome. Understanding the global regulation of developmental control genes may provide a new perspective on development in the era genomics.
Collapse
Affiliation(s)
- Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA.
| | | |
Collapse
|
31
|
Abstract
Enhancers act over many kilobase pairs to activate target promoters, but their activity is constrained by insulator elements that prevent indiscriminate activation of nearby genes. In the July 1, 2009, issue of Genes & Development, Chopra and colleagues (pp. 1505-1509) report that promoters containing a stalled Pol II are activated by enhancers, but these promoters also serve as insulators that block enhancers from reaching more distal genes. This new class of insulators provide critical clues to regulatory mechanisms.
Collapse
Affiliation(s)
- Leighton J. Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - John T. Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| |
Collapse
|
32
|
7SK snRNP/P-TEFb couples transcription elongation with alternative splicing and is essential for vertebrate development. Proc Natl Acad Sci U S A 2009; 106:7798-803. [PMID: 19416841 DOI: 10.1073/pnas.0903188106] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic gene expression is commonly controlled at the level of RNA polymerase II (RNAPII) pausing subsequent to transcription initiation. Transcription elongation is stimulated by the positive transcription elongation factor b (P-TEFb) kinase, which is suppressed within the 7SK small nuclear ribonucleoprotein (7SK snRNP). However, the biogenesis and functional significance of 7SK snRNP remain poorly understood. Here, we report that LARP7, BCDIN3, and the noncoding 7SK small nuclear RNA (7SK) are vital for the formation and stability of a cell stress-resistant core 7SK snRNP. Our functional studies demonstrate that 7SK snRNP is not only critical for controlling transcription elongation, but also for regulating alternative splicing of pre-mRNAs. Using a transient expression splicing assay, we find that 7SK snRNP disintegration promotes inclusion of an alternative exon via the increased occupancy of P-TEFb, Ser2-phosphorylated (Ser2-P) RNAPII, and the splicing factor SF2/ASF at the minigene. Importantly, knockdown of larp7 or bcdin3 orthologues in zebrafish embryos destabilizes 7SK and causes severe developmental defects and aberrant splicing of analyzed transcripts. These findings reveal a key role for P-TEFb in coupling transcription elongation with alternative splicing, and suggest that maintaining core 7SK snRNP is essential for vertebrate development.
Collapse
|
33
|
Chopra VS, Hong JW, Levine M. Regulation of Hox gene activity by transcriptional elongation in Drosophila. Curr Biol 2009; 19:688-93. [PMID: 19345103 DOI: 10.1016/j.cub.2009.02.055] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 02/23/2009] [Accepted: 02/25/2009] [Indexed: 10/20/2022]
Abstract
Hox genes control the anterior-posterior patterning of most metazoan embryos. Their sequential expression is initially established by the segmentation gene cascade in the early Drosophila embryo [1]. The maintenance of these patterns depends on the Polycomb group (PcG) and trithorax group (trxG) complexes during the remainder of the life cycle [2]. We provide both genetic and molecular evidence that the Hox genes are subject to an additional tier of regulation, i.e., at the level of transcription elongation. Both Ultrabithorax (Ubx) and Abdominal-B (Abd-B) genes contain stalled or paused RNA polymerase II (Pol II) even when silent [3, 4]. The Pol II elongation factors Elongin-A and Cdk9 are essential for optimal Ubx and Abd-B expression. Mitotic recombination assays suggest that these elongation factors are also important for the regulation of Notch-, EGF-, and Dpp-signaling genes. Stalled Pol II persists in tissues where Ubx and Abd-B are silenced by the PcG complex. We propose that stalling fosters both the rapid induction and precise silencing of Hox gene expression during development.
Collapse
Affiliation(s)
- Vivek S Chopra
- Division of Genetics, Center for Integrative Genomics, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | | | | |
Collapse
|
34
|
Gilchrist DA, Fargo DC, Adelman K. Using ChIP-chip and ChIP-seq to study the regulation of gene expression: genome-wide localization studies reveal widespread regulation of transcription elongation. Methods 2009; 48:398-408. [PMID: 19275938 DOI: 10.1016/j.ymeth.2009.02.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 02/25/2009] [Accepted: 02/27/2009] [Indexed: 10/21/2022] Open
Abstract
Transcription is a sophisticated multi-step process in which RNA polymerase II (Pol II) transcribes a DNA template into RNA in concert with a broad array of transcription initiation, elongation, capping, termination, and histone modifying factors. Recent global analyses of Pol II distribution have indicated that many genes are regulated during the elongation phase, shedding light on a previously underappreciated mechanism for controlling gene expression. Understanding how various factors regulate transcription elongation in living cells has been greatly aided by chromatin immunoprecipitation (ChIP) studies, which can provide spatial and temporal resolution of protein-DNA binding events. The coupling of ChIP with DNA microarray and high-throughput sequencing technologies (ChIP-chip and ChIP-seq) has significantly increased the scope of ChIP studies and genome-wide maps of Pol II or elongation factor binding sites can now be readily produced. However, while ChIP-chip/ChIP-seq data allow for high-resolution localization of protein-DNA binding sites, they are not sufficient to dissect protein function. Here we describe techniques for coupling ChIP-chip/ChIP-seq with genetic, chemical, and experimental manipulation to obtain mechanistic insight from genome-wide protein-DNA binding studies. We have employed these techniques to discern immature promoter-proximal Pol II from productively elongating Pol II, and infer a critical role for the transition between initiation and full elongation competence in regulating development and gene induction in response to environmental signals.
Collapse
Affiliation(s)
- Daniel A Gilchrist
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | | |
Collapse
|
35
|
Gilmour DS, Fan R. Detecting transcriptionally engaged RNA polymerase in eukaryotic cells with permanganate genomic footprinting. Methods 2009; 48:368-74. [PMID: 19272453 DOI: 10.1016/j.ymeth.2009.02.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/23/2009] [Accepted: 02/25/2009] [Indexed: 11/27/2022] Open
Abstract
Analysis of the distribution of RNA polymerase II on the genomes of Drosophila and human cells using in vivo protein-DNA crosslinking reveals that RNA polymerase II (Pol II) is concentrated at the 5'-ends of thousands of genes. This appears to be irrespective of transcription levels. Hence, a potential regulatory step in the transcription of many genes occurs after Pol II has associated with the promoter. The protein-DNA crosslinking technique widely used to monitor Pol II and other proteins on chromosomes in vivo, however, does not reveal if Pol II is transcriptionally engaged on DNA. Genomic footprinting with potassium permanganate provides one method for detecting transcriptionally engaged Pol II. Using this approach, we have determined that the Pol II associated with the promoters of many genes has initiated transcription but paused in the region 20-50 nucleotides from the start. Here we describe the application of this method in Drosophila and human cells. The method should prove useful in assessing if promoter bound Pol II has engaged in transcription and for investigating the establishment and regulation of transcriptionally engaged Pol II.
Collapse
Affiliation(s)
- David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 208 Althouse, University Park, PA 16802, United States.
| | | |
Collapse
|
36
|
Postrecruitment regulation of RNA polymerase II directs rapid signaling responses at the promoters of estrogen target genes. Mol Cell Biol 2008; 29:1123-33. [PMID: 19103744 DOI: 10.1128/mcb.00841-08] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Under classical models for signal-dependent transcription in eukaryotes, DNA-binding activator proteins regulate the recruitment of RNA polymerase II (Pol II) to a set of target promoters. However, recent studies, as well as our results herein, show that Pol II is widely distributed (i.e., "preloaded") at the promoters of many genes prior to specific signaling events. How Pol II recruitment and Pol II preloading fit within a unified model of gene regulation is unclear. In addition, the mechanisms through which cellular signals activate preloaded Pol II across mammalian genomes remain largely unknown. We show here that the predominant genomic outcome of estrogen signaling is the postrecruitment regulation of Pol II activity at target gene promoters, likely through specific changes in Pol II phosphorylation rather than through recruitment of Pol II to the promoters. Furthermore, we show that negative elongation factor binds to estrogen target promoters in conjunction with preloaded Pol II and represses gene expression until the appropriate signal is received. Finally, our studies reveal that the estrogen-dependent activation of preloaded Pol II facilitates rapid gene regulatory responses which play important physiological roles in regulating estrogen signaling itself. Our results reveal a broad use of postrecruitment Pol II regulation by the estrogen signaling pathway, a mode of regulation that is likely to apply to a wide variety of signal-regulated pathways.
Collapse
|
37
|
Gilmour DS. Promoter proximal pausing on genes in metazoans. Chromosoma 2008; 118:1-10. [PMID: 18830703 DOI: 10.1007/s00412-008-0182-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 09/14/2008] [Accepted: 09/14/2008] [Indexed: 10/21/2022]
Abstract
The past two decades of research into transcriptional control of protein-encoding genes in eukaryotes have focused on regulatory mechanisms that act by controlling the recruitment of Pol II to a gene's promoter. Recent genome-wide analyses of the distribution of Pol II indicates that Pol II is concentrated in the promoter regions of thousands of genes in human and Drosophila cells. In many cases, Pol II may have initiated transcription but paused in the promoter proximal region. Hence, release of Pol II from the promoter region into the body of a gene is now recognized as a common rate-limiting step in the control of gene expression. Notably, most genes with paused Pol II are expressed indicating that the pause can be transient. What causes Pol II to concentrate in the promoter region and how it is released to transcribe a gene are the focus of this review.
Collapse
Affiliation(s)
- David S Gilmour
- Center for Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| |
Collapse
|
38
|
Stofanko M, Kwon SY, Badenhorst P. A misexpression screen to identify regulators of Drosophila larval hemocyte development. Genetics 2008; 180:253-67. [PMID: 18757933 PMCID: PMC2535679 DOI: 10.1534/genetics.108.089094] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 07/14/2008] [Indexed: 12/19/2022] Open
Abstract
In Drosophila, defense against foreign pathogens is mediated by an effective innate immune system, the cellular arm of which is composed of circulating hemocytes that engulf bacteria and encapsulate larger foreign particles. Three hemocyte types occur: plasmatocytes, crystal cells, and lamellocytes. The most abundant larval hemocyte type is the plasmatocyte, which is responsible for phagocytosis and is present either in circulation or in adherent sessile domains under the larval cuticle. The mechanisms controlling differentiation of plasmatocytes and their migration toward these sessile compartments are unclear. To address these questions we have conducted a misexpression screen using the plasmatocyte-expressed GAL4 driver Peroxidasin-GAL4 (Pxn-GAL4) and existing enhancer-promoter (EP) and EP yellow (EY) transposon libraries to systematically misexpress approximately 20% of Drosophila genes in larval hemocytes. The Pxn-GAL4 strain also contains a UAS-GFP reporter enabling hemocyte phenotypes to be visualized in the semitransparent larvae. Among 3412 insertions screened we uncovered 101 candidate hemocyte regulators. Some of these are known to control hemocyte development, but the majority either have no characterized function or are proteins of known function not previously implicated in hemocyte development. We have further analyzed three candidate genes for changes in hemocyte morphology, cell-cell adhesion properties, phagocytosis activity, and melanotic tumor formation.
Collapse
Affiliation(s)
- Martin Stofanko
- Institute of Biomedical Research, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | | | | |
Collapse
|
39
|
A simplified miRNA-based gene silencing method for Drosophila melanogaster. Dev Biol 2008; 321:482-90. [PMID: 18598689 DOI: 10.1016/j.ydbio.2008.06.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 06/04/2008] [Accepted: 06/10/2008] [Indexed: 11/21/2022]
Abstract
MicroRNA-based RNA interference is commonly used to produce loss-of-function phenotypes in mammalian systems, but is used only sparingly in invertebrates such as Caenorhabditis elegans and Drosophila melanogaster. Here, we evaluate this method in transgenic strains of D. melanogaster and cultured S2 cells. High throughput-ready expression vectors were developed that permit rapid cloning of synthetic hairpin RNAs. As proof of concept, this method was used for the efficient silencing of dpp gene activity in the adult wing, and the analysis of the general RNA Polymerase II (Pol II) elongation factor, Nelf-E.
Collapse
|
40
|
Promoter elements associated with RNA Pol II stalling in the Drosophila embryo. Proc Natl Acad Sci U S A 2008; 105:7762-7. [PMID: 18505835 DOI: 10.1073/pnas.0802406105] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RNA Polymerase II (Pol II) is bound to the promoter regions of many or most developmental control genes before their activation during Drosophila embryogenesis. It has been suggested that Pol II stalling is used to produce dynamic and rapid responses of developmental patterning genes to transient cues such as extracellular signaling molecules. Here, we present a combined computational and experimental analysis of stalled promoters to determine how they come to bind Pol II in the early Drosophila embryo. At least one-fourth of the stalled promoters contain a shared sequence motif, the "pause button" (PB): KCGRWCG. The PB motif is sometimes located in the position of the DPE, and over one-fifth of the stalled promoters contain the following arrangement of core elements: GAGA, Inr, PB, and/or DPE. This arrangement was used to identify additional stalled promoters in the Drosophila genome, and permanganate footprint assays were used to confirm that the segmentation gene engrailed contains paused Pol II as seen for heat-shock genes. We discuss different models for Pol II binding and gene activation in the early embryo.
Collapse
|
41
|
Abstract
Recent global analyses have determined that many Drosophila and human genes have engaged polymerase molecules trapped immediately downstream of promoters. These results strongly implicate RNA polymerase II elongation control as a major regulator of differentiation and development.
Collapse
Affiliation(s)
- David H Price
- Biochemistry Department, University of Iowa, Iowa City, IA 52240, USA.
| |
Collapse
|
42
|
Core LJ, Lis JT. Transcription regulation through promoter-proximal pausing of RNA polymerase II. Science 2008; 319:1791-2. [PMID: 18369138 DOI: 10.1126/science.1150843] [Citation(s) in RCA: 299] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent work has shown that the RNA polymerase II enzyme pauses at a promoter-proximal site of many genes in Drosophila and mammals. This rate-limiting step occurs after recruitment and initiation of RNA polymerase II at a gene promoter. This stage in early elongation appears to be an important and broadly used target of gene regulation.
Collapse
Affiliation(s)
- Leighton J Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | |
Collapse
|
43
|
Drosophila Ebi mediates Snail-dependent transcriptional repression through HDAC3-induced histone deacetylation. EMBO J 2008; 27:898-909. [PMID: 18309295 DOI: 10.1038/emboj.2008.26] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Accepted: 02/07/2008] [Indexed: 01/14/2023] Open
Abstract
The Drosophila Snail protein is a transcriptional repressor that is necessary for mesoderm formation. Here, we identify the Ebi protein as an essential Snail co-repressor. In ebi mutant embryos, Snail target genes are derepressed in the presumptive mesoderm. Ebi and Snail interact both genetically and physically. We identify a Snail domain that is sufficient for Ebi binding, and which functions independently of another Snail co-repressor, Drosophila CtBP. This Ebi interaction domain is conserved among all insect Snail-related proteins, is a potent repression domain and is required for Snail function in transgenic embryos. In mammalian cells, the Ebi homologue TBL1 is part of the NCoR/SMRT-HDAC3 (histone deacetylase 3) co-repressor complex. We found that Ebi interacts with Drosophila HDAC3, and that HDAC3 knockdown or addition of a HDAC inhibitor impairs Snail-mediated repression in cells. In the early embryo, Ebi is recruited to a Snail target gene in a Snail-dependent manner, which coincides with histone hypoacetylation. Our results demonstrate that Snail requires the combined activities of Ebi and CtBP, and indicate that histone deacetylation is a repression mechanism in early Drosophila development.
Collapse
|
44
|
Abstract
Transcriptional repressor proteins play key roles in the control of gene expression in development. For the Drosophila embryo, the following two functional classes of repressors have been described: short-range repressors such as Knirps that locally inhibit the activity of enhancers and long-range repressors such as Hairy that can dominantly inhibit distal elements. Several long-range repressors interact with Groucho, a conserved corepressor that is homologous to mammalian TLE proteins. Groucho interacts with histone deacetylases and histone proteins, suggesting that it may effect repression by means of chromatin modification; however, it is not known how long-range effects are mediated. Using embryo chromatin immunoprecipitation, we have analyzed a Hairy-repressible gene in the embryo during activation and repression. When inactivated, repressors, activators, and coactivators cooccupy the promoter, suggesting that repression is not accomplished by the displacement of activators or coactivators. Strikingly, the Groucho corepressor is found to be recruited to the transcribed region of the gene, contacting a region of several kilobases, concomitant with a loss of histone H3 and H4 acetylation. Groucho has been shown to form higher-order complexes in vitro; thus, our observations suggest that long-range effects may be mediated by a "spreading" mechanism, modifying chromatin over extensive regions to inhibit transcription.
Collapse
|
45
|
Amir-Zilberstein L, Dikstein R. Interplay between E-box and NF-κB in Regulation of A20 Gene by DRB Sensitivity-inducing Factor (DSIF). J Biol Chem 2008; 283:1317-1323. [DOI: 10.1074/jbc.m706767200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
46
|
Muse GW, Gilchrist DA, Nechaev S, Shah R, Parker JS, Grissom SF, Zeitlinger J, Adelman K. RNA polymerase is poised for activation across the genome. Nat Genet 2007; 39:1507-11. [PMID: 17994021 DOI: 10.1038/ng.2007.21] [Citation(s) in RCA: 583] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 09/07/2007] [Indexed: 02/08/2023]
Abstract
Regulation of gene expression is integral to the development and survival of all organisms. Transcription begins with the assembly of a pre-initiation complex at the gene promoter, followed by initiation of RNA synthesis and the transition to productive elongation. In many cases, recruitment of RNA polymerase II (Pol II) to a promoter is necessary and sufficient for activation of genes. However, there are a few notable exceptions to this paradigm, including heat shock genes and several proto-oncogenes, whose expression is attenuated by regulated stalling of polymerase elongation within the promoter-proximal region. To determine the importance of polymerase stalling for transcription regulation, we carried out a genome-wide search for Drosophila melanogaster genes with Pol II stalled within the promoter-proximal region. Our data show that stalling is widespread, occurring at hundreds of genes that respond to stimuli and developmental signals. This finding indicates a role for regulation of polymerase elongation in the transcriptional responses to dynamic environmental and developmental cues.
Collapse
Affiliation(s)
- Ginger W Muse
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Zeitlinger J, Stark A, Kellis M, Hong JW, Nechaev S, Adelman K, Levine M, Young RA. RNA polymerase stalling at developmental control genes in the Drosophila melanogaster embryo. Nat Genet 2007; 39:1512-6. [PMID: 17994019 DOI: 10.1038/ng.2007.26] [Citation(s) in RCA: 594] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 09/07/2007] [Indexed: 11/09/2022]
Abstract
It is widely assumed that the key rate-limiting step in gene activation is the recruitment of RNA polymerase II (Pol II) to the core promoter. Although there are well-documented examples in which Pol II is recruited to a gene but stalls, a general role for Pol II stalling in development has not been established. We have carried out comprehensive Pol II chromatin immunoprecipitation microarray (ChIP-chip) assays in Drosophila embryos and identified three distinct Pol II binding behaviors: active (uniform binding across the entire transcription unit), no binding, and stalled (binding at the transcription start site). The notable feature of the approximately 10% genes that are stalled is that they are highly enriched for developmental control genes, which are either repressed or poised for activation during later stages of embryogenesis. We propose that Pol II stalling facilitates rapid temporal and spatial changes in gene activity during development.
Collapse
Affiliation(s)
- Julia Zeitlinger
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, Massachusetts 02142, USA
| | | | | | | | | | | | | | | |
Collapse
|