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Biernat E, Verma M, Govind CK. Genome-wide regulation of Pol II, FACT, and Spt6 occupancies by RSC in Saccharomyces cerevisiae. Gene 2024; 893:147959. [PMID: 37923091 PMCID: PMC10872467 DOI: 10.1016/j.gene.2023.147959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/17/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
RSC (remodels the structure of chromatin) is an essential ATP-dependent chromatin remodeling complex in Saccharomyces cerevisiae. RSC utilizes its ATPase subunit, Sth1, to slide or remove nucleosomes. RSC has been shown to regulate the width of the nucleosome-depleted regions (NDRs) by sliding the flanking nucleosomes away from NDRs. As such, when RSC is depleted, nucleosomes encroach NDRs, leading to transcription initiation defects. In this study, we examined the effects of the catalytic-dead Sth1 on transcription and compared them to those observed during acute and rapid Sth1 depletion by auxin-induced degron strategy. We found that rapid depletion of Sth1 reduces recruitment of TBP and Pol II in highly transcribed genes, as would be expected considering its role in regulating chromatin structure at promoters. In contrast, cells harboring the catalytic-dead Sth1 (sth1-K501R) exhibited a severe reduction in TBP binding, but, surprisingly, also displayed a substantial accumulation in Pol II occupancies within coding regions. The Pol II occupancies further increased upon depleting endogenous Sth1 in the catalytic-dead mutant, suggesting that the inactive Sth1 contributes to Pol II accumulation in coding regions. Notwithstanding the Pol II increase, the ORF occupancies of histone chaperones, FACT and Spt6 were significantly reduced in the mutant. These results suggest a potential role for RSC in recruiting/retaining these chaperones in coding regions. Pol II accumulation despite substantial reductions in TBP, FACT, and Spt6 occupancies in the catalytic-dead mutant could indicate severe transcription elongation and termination defects. Such defects would be consistent with studies showing that RSC is recruited to coding regions in a transcription-dependent manner. Thus, these findings imply a role for RSC in transcription elongation and termination processes, in addition to its established role in transcription initiation.
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Affiliation(s)
- Emily Biernat
- Department of Biological Sciences, Mathematics and Science Center, Oakland University, Rochester, MI 48309, USA
| | - Mansi Verma
- Department of Biological Sciences, Mathematics and Science Center, Oakland University, Rochester, MI 48309, USA
| | - Chhabi K Govind
- Department of Biological Sciences, Mathematics and Science Center, Oakland University, Rochester, MI 48309, USA.
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Biernat E, Kinney J, Dunlap K, Rizza C, Govind CK. The RSC complex remodels nucleosomes in transcribed coding sequences and promotes transcription in Saccharomyces cerevisiae. Genetics 2021; 217:6133232. [PMID: 33857307 PMCID: PMC8049546 DOI: 10.1093/genetics/iyab021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/05/2021] [Indexed: 01/06/2023] Open
Abstract
RSC (Remodels the Structure of Chromatin) is a conserved ATP-dependent chromatin remodeling complex that regulates many biological processes, including transcription by RNA polymerase II (Pol II). We report that RSC contributes in generating accessible nucleosomes in transcribed coding sequences (CDSs). RSC MNase ChIP-seq data revealed that RSC-bound nucleosome fragments were very heterogenous (∼80 bp to 180 bp) compared to a sharper profile displayed by the MNase inputs (140 bp to 160 bp), supporting the idea that RSC promotes accessibility of nucleosomal DNA. Notably, RSC binding to +1 nucleosomes and CDSs, but not with -1 nucleosomes, strongly correlated with Pol II occupancies, suggesting that RSC enrichment in CDSs is linked to transcription. We also observed that Pol II associates with nucleosomes throughout transcribed CDSs, and similar to RSC, Pol II-protected fragments were highly heterogenous, consistent with the idea that Pol II interacts with remodeled nucleosomes in CDSs. This idea is supported by the observation that the genes harboring high-levels of Pol II in their CDSs were the most strongly affected by ablating RSC function. Additionally, rapid nuclear depletion of Sth1 decreases nucleosome accessibility and results in accumulation of Pol II in highly transcribed CDSs. This is consistent with a slower clearance of elongating Pol II in cells with reduced RSC function, and is distinct from the effect of RSC depletion on PIC assembly. Altogether, our data provide evidence in support of the role of RSC in promoting Pol II elongation, in addition to its role in regulating transcription initiation.
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Affiliation(s)
- Emily Biernat
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Jeena Kinney
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Kyle Dunlap
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Christian Rizza
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Chhabi K Govind
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
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Acetylation-Dependent Recruitment of the FACT Complex and Its Role in Regulating Pol II Occupancy Genome-Wide in Saccharomyces cerevisiae. Genetics 2018; 209:743-756. [PMID: 29695490 DOI: 10.1534/genetics.118.300943] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 04/23/2018] [Indexed: 12/23/2022] Open
Abstract
Histone chaperones, chromatin remodelers, and histone modifying complexes play a critical role in alleviating the nucleosomal barrier for DNA-dependent processes. Here, we have examined the role of two highly conserved yeast (Saccharomyces cerevisiae) histone chaperones, facilitates chromatin transcription (FACT) and Spt6, in regulating transcription. We show that the H3 tail contributes to the recruitment of FACT to coding sequences in a manner dependent on acetylation. We found that deleting a H3 histone acetyltransferase Gcn5 or mutating lysines on the H3 tail impairs FACT recruitment at ADH1 and ARG1 genes. However, deleting the H4 tail or mutating the H4 lysines failed to dampen FACT occupancy in coding regions. Additionally, we show that FACT depletion reduces RNA polymerase II (Pol II) occupancy genome-wide. Spt6 depletion leads to a reduction in Pol II occupancy toward the 3'-end, in a manner dependent on the gene length. Severe transcription and histone-eviction defects were also observed in a strain that was impaired for Spt6 recruitment (spt6Δ202) and depleted of FACT. Importantly, the severity of the defect strongly correlated with wild-type Pol II occupancies at these genes, indicating critical roles for Spt6 and Spt16 in promoting high-level transcription. Collectively, our results show that both FACT and Spt6 are important for transcription globally and may participate during different stages of transcription.
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Recruitment of Saccharomyces cerevisiae Cmr1/Ydl156w to Coding Regions Promotes Transcription Genome Wide. PLoS One 2016; 11:e0148897. [PMID: 26848854 PMCID: PMC4744024 DOI: 10.1371/journal.pone.0148897] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 01/25/2016] [Indexed: 12/03/2022] Open
Abstract
Cmr1 (changed mutation rate 1) is a largely uncharacterized nuclear protein that has recently emerged in several global genetic interaction and protein localization studies. It clusters with proteins involved in DNA damage and replication stress response, suggesting a role in maintaining genome integrity. Under conditions of proteasome inhibition or replication stress, this protein localizes to distinct sub-nuclear foci termed as intranuclear quality control (INQ) compartments, which sequester proteins for their subsequent degradation. Interestingly, it also interacts with histones, chromatin remodelers and modifiers, as well as with proteins involved in transcription including subunits of RNA Pol I and Pol III, but not with those of Pol II. It is not known whether Cmr1 plays a role in regulating transcription of Pol II target genes. Here, we show that Cmr1 is recruited to the coding regions of transcribed genes of S. cerevisiae. Cmr1 occupancy correlates with the Pol II occupancy genome-wide, indicating that it is recruited to coding sequences in a transcription-dependent manner. Cmr1-enriched genes include Gcn4 targets and ribosomal protein genes. Furthermore, our results show that Cmr1 recruitment to coding sequences is stimulated by Pol II CTD kinase, Kin28, and the histone deacetylases, Rpd3 and Hos2. Finally, our genome-wide analyses implicate Cmr1 in regulating Pol II occupancy at transcribed coding sequences. However, it is dispensable for maintaining co-transcriptional histone occupancy and histone modification (acetylation and methylation). Collectively, our results show that Cmr1 facilitates transcription by directly engaging with transcribed coding regions.
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Spain MM, Ansari SA, Pathak R, Palumbo MJ, Morse RH, Govind CK. The RSC complex localizes to coding sequences to regulate Pol II and histone occupancy. Mol Cell 2014; 56:653-66. [PMID: 25457164 DOI: 10.1016/j.molcel.2014.10.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 10/24/2022]
Abstract
ATP-dependent chromatin remodelers regulate chromatin structure during multiple stages of transcription. We report that RSC, an essential chromatin remodeler, is recruited to the open reading frames (ORFs) of actively transcribed genes genome wide, suggesting a role for RSC in regulating transcription elongation. Consistent with such a role, Pol II occupancy in the ORFs of weakly transcribed genes is drastically reduced upon depletion of the RSC catalytic subunit Sth1. RSC inactivation also reduced histone H3 occupancy across transcribed regions. Remarkably, the strongest effects on Pol II and H3 occupancy were confined to the genes displaying the greatest RSC ORF enrichment. Additionally, RSC recruitment to the ORF requires the activities of the SAGA and NuA4 HAT complexes and is aided by the activities of the Pol II CTD Ser2 kinases Bur1 and Ctk1. Overall, our findings strongly implicate ORF-associated RSC in governing Pol II function and in maintaining chromatin structure over transcribed regions.
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Affiliation(s)
- Marla M Spain
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Suraiya A Ansari
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Rakesh Pathak
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Michael J Palumbo
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Randall H Morse
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Chhabi K Govind
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA.
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Histone deacetylases and phosphorylated polymerase II C-terminal domain recruit Spt6 for cotranscriptional histone reassembly. Mol Cell Biol 2014; 34:4115-29. [PMID: 25182531 DOI: 10.1128/mcb.00695-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Spt6 is a multifunctional histone chaperone involved in the maintenance of chromatin structure during elongation by RNA polymerase II (Pol II). Spt6 has a tandem SH2 (tSH2) domain within its C terminus that recognizes Pol II C-terminal domain (CTD) peptides phosphorylated on Ser2, Ser5, or Try1 in vitro. Deleting the tSH2 domain, however, only has a partial effect on Spt6 occupancy in vivo, suggesting that more complex mechanisms are involved in the Spt6 recruitment. Our results show that the Ser2 kinases Bur1 and Ctk1, but not the Ser5 kinase Kin28, cooperate in recruiting Spt6, genome-wide. Interestingly, the Ser2 kinases promote the association of Spt6 in early transcribed regions and not toward the 3' ends of genes, where phosphorylated Ser2 reaches its maximum level. In addition, our results uncover an unexpected role for histone deacetylases (Rpd3 and Hos2) in promoting Spt6 interaction with elongating Pol II. Finally, our data suggest that phosphorylation of the Pol II CTD on Tyr1 promotes the association of Spt6 with the 3' ends of transcribed genes, independently of Ser2 phosphorylation. Collectively, our results show that a complex network of interactions, involving the Spt6 tSH2 domain, CTD phosphorylation, and histone deacetylases, coordinate the recruitment of Spt6 to transcribed genes in vivo.
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Yesudhas D, Gosu V, Anwar MA, Choi S. Multiple roles of toll-like receptor 4 in colorectal cancer. Front Immunol 2014; 5:334. [PMID: 25076949 PMCID: PMC4097957 DOI: 10.3389/fimmu.2014.00334] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 07/01/2014] [Indexed: 12/14/2022] Open
Abstract
Toll-like receptor (TLR) signaling has been implicated in the inflammatory responses in intestinal epithelial cells (IECs). Such inflammatory signals mediate complex interactions between commensal bacteria and TLRs and are required for IEC proliferation, immune response, repair, and homeostasis. The upregulation of certain TLRs in colorectal cancer (CRC) tissues suggests that TLRs may play an essential role in the prognosis of chronic and inflammatory diseases that ultimately culminate in CRC. Here, we provide a comprehensive review of the literature on the involvement of the TLR pathway in the initiation, progression, and metastasis of CRC, as well as inherited genetic variation and epigenetic regulation. The differential expression of TLRs in epithelial cells has also been discussed. In particular, we emphasize the physiological role of TLR4 in CRC development and pathogenesis, and propose novel and promising approaches for CRC therapeutics with the aid of TLR ligands.
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Affiliation(s)
- Dhanusha Yesudhas
- Department of Molecular Science and Technology, Ajou University , Suwon , South Korea
| | - Vijayakumar Gosu
- Department of Molecular Science and Technology, Ajou University , Suwon , South Korea
| | - Muhammad Ayaz Anwar
- Department of Molecular Science and Technology, Ajou University , Suwon , South Korea
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University , Suwon , South Korea
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