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Jensen CL, Chen LF, Swigut T, Crocker OJ, Yao D, Bassik MC, Ferrell JE, Boettiger AN, Wysocka J. Long range regulation of transcription scales with genomic distance in a gene specific manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.19.604327. [PMID: 39071420 PMCID: PMC11275926 DOI: 10.1101/2024.07.19.604327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
While critical for tuning the timing and level of transcription, enhancer communication with distal promoters is not well understood. Here we bypass the need for sequence-specific transcription factors and recruit activators directly using CARGO-VPR, an approach for targeting dCas9-VPR using a multiplexed array of RNA guides. We show that this approach achieves effective activator recruitment to arbitrary genomic sites, even those inaccessible by single dCas9. We utilize CARGO-VPR across the Prdm8-Fgf5 locus in mESCs, where neither gene is expressed. We demonstrate that while activator recruitment to any tested region results in transcriptional induction of at least one gene, the expression level strongly depends on the genomic distance between the promoter and activator recruitment site. However, the expression-distance relationship for each gene scales distinctly in a manner not attributable to differences in 3D contact frequency, promoter DNA sequence or presence of the repressive chromatin marks at the locus.
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Rodríguez TC, Yurkovetskiy L, Nagalekshmi K, Lam CHO, Jazbec E, Maitland SA, Wolfe SA, Sontheimer EJ, Luban J. PRC1.6 localizes on chromatin with the human silencing hub (HUSH) complex for promoter-specific silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603173. [PMID: 39026796 PMCID: PMC11257501 DOI: 10.1101/2024.07.12.603173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
An obligate step in the life cycle of HIV-1 and other retroviruses is the establishment of the provirus in target cell chromosomes. Transcriptional regulation of proviruses is complex, and understanding the mechanisms underlying this regulation has ramifications for fundamental biology, human health, and gene therapy implementation. The three core components of the Human Silencing Hub (HUSH) complex, TASOR, MPHOSPH8 (MPP8), and PPHLN1 (Periphilin 1), were identified in forward genetic screens for host genes that repress provirus expression. Subsequent loss-of-function screens revealed accessory proteins that collaborate with the HUSH complex to silence proviruses in particular contexts. To identify proteins associated with a HUSH complex-repressed provirus in human cells, we developed a technique, Provirus Proximal Proteomics, based on proximity labeling with C-BERST (dCas9-APEX2 biotinylation at genomic elements by restricted spatial tagging). Our screen exploited a lentiviral reporter that is silenced by the HUSH complex in a manner that is independent of the integration site in chromatin. Our data reveal that proviruses silenced by the HUSH complex are associated with DNA repair, mRNA processing, and transcriptional silencing proteins, including L3MBTL2, a member of the non-canonical polycomb repressive complex 1.6 (PRC1.6). A forward genetic screen confirmed that PRC1.6 components L3MBTL2 and MGA contribute to HUSH complex-mediated silencing. PRC1.6 was then shown to silence HUSH-sensitive proviruses in a promoter-specific manner. Genome wide profiling showed striking colocalization of the PRC1.6 and HUSH complexes on chromatin, primarily at sites of active promoters. Finally, PRC1.6 binding at a subset of genes that are silenced by the HUSH complex was dependent on the core HUSH complex component MPP8. These studies offer new tools with great potential for studying the transcriptional regulation of proviruses and reveal crosstalk between the HUSH complex and PRC1.6.
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Affiliation(s)
- Tomás C. Rodríguez
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Leonid Yurkovetskiy
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Karthika Nagalekshmi
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Chin Hung Oscar Lam
- Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Eva Jazbec
- Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Stacy A. Maitland
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Scot A. Wolfe
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Erik J. Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Jeremy Luban
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
- Massachusetts Consortium on Pathogen Readiness, Boston, MA 02115, USA
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Jensvold ZD, Christenson AE, Flood JR, Lewis PW. Interplay between Two Paralogous Human Silencing Hub (HuSH) Complexes in Regulating LINE-1 Element Silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.28.573526. [PMID: 38313255 PMCID: PMC10836065 DOI: 10.1101/2023.12.28.573526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
The Human Silencing Hub (HuSH) complex is composed of TASOR, MPP8, and PPHLN1 subunits and serves as a conserved protein complex responsible for silencing transposable elements in vertebrate animals. Despite its importance, the regulatory mechanisms and recruitment dynamics governing this complex remain poorly understood. In this study, we have identified a second HuSH complex, termed HuSH2, centered around TASOR2, a paralog of the core TASOR protein in HuSH. Our findings indicate that every subunit in both HuSH and HuSH2 has an important role in achieving precise genomic localization to distinct, non-overlapping genomic loci. We utilized in silico protein structure prediction to simulate the interactions between MPP8 and both TASOR paralogs. Drawing on the insights gained from these predictions, we implemented amino acid substitutions that interfered with the binding of MPP8 to each HuSH complex. Leveraging these MPP8 transgenes and other constructs, we identified an important role played by the relative quantities of HuSH complexes in controlling the activity of LINE-1 elements. Furthermore, our results suggest that dynamic changes in TASOR and TASOR2 expression enable cells to finely tune the extent of HuSH-mediated silencing. Our study provides insights into the intricate interplay between HuSH complexes, illuminating their important role in the regulation of retrotransposon silencing.
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Affiliation(s)
- Zena D Jensvold
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53715, USA
| | - Anna E Christenson
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53715, USA
| | - Julia R Flood
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53715, USA
| | - Peter W Lewis
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53715, USA
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Palazzo AF, Qiu Y, Kang YM. mRNA nuclear export: how mRNA identity features distinguish functional RNAs from junk transcripts. RNA Biol 2024; 21:1-12. [PMID: 38091265 PMCID: PMC10732640 DOI: 10.1080/15476286.2023.2293339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
The division of the cellular space into nucleoplasm and cytoplasm promotes quality control mechanisms that prevent misprocessed mRNAs and junk RNAs from gaining access to the translational machinery. Here, we explore how properly processed mRNAs are distinguished from both misprocessed mRNAs and junk RNAs by the presence or absence of various 'identity features'.
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Affiliation(s)
| | - Yi Qiu
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yoon Mo Kang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Ait Said M, Bejjani F, Abdouni A, Ségéral E, Emiliani S. Premature transcription termination complex proteins PCF11 and WDR82 silence HIV-1 expression in latently infected cells. Proc Natl Acad Sci U S A 2023; 120:e2313356120. [PMID: 38015843 PMCID: PMC10710072 DOI: 10.1073/pnas.2313356120] [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: 08/03/2023] [Accepted: 10/30/2023] [Indexed: 11/30/2023] Open
Abstract
Postintegration transcriptional silencing of HIV-1 leads to the establishment of a pool of latently infected cells. In these cells, mechanisms controlling RNA Polymerase II (RNAPII) pausing and premature transcription termination (PTT) remain to be explored. Here, we found that the cleavage and polyadenylation (CPA) factor PCF11 represses HIV-1 expression independently of the other subunits of the CPA complex or the polyadenylation signal located at the 5' LTR. We show that PCF11 interacts with the RNAPII-binding protein WDR82. Knock-down of PCF11 or WDR82 reactivated HIV-1 expression in latently infected cells. To silence HIV-1 transcription, PCF11 and WDR82 are specifically recruited at the promoter-proximal region of the provirus in an interdependent manner. Codepletion of PCF11 and WDR82 indicated that they act on the same pathway to repress HIV expression. These findings reveal PCF11/WDR82 as a PTT complex silencing HIV-1 expression in latently infected cells.
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Affiliation(s)
- Melissa Ait Said
- Université Paris Cité, Institut Cochin, INSERM, CNRS, ParisF-75014, France
| | - Fabienne Bejjani
- Université Paris Cité, Institut Cochin, INSERM, CNRS, ParisF-75014, France
| | - Ahmed Abdouni
- Université Paris Cité, Institut Cochin, INSERM, CNRS, ParisF-75014, France
| | - Emmanuel Ségéral
- Université Paris Cité, Institut Cochin, INSERM, CNRS, ParisF-75014, France
| | - Stéphane Emiliani
- Université Paris Cité, Institut Cochin, INSERM, CNRS, ParisF-75014, France
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Li Z, Duan S, Hua X, Xu X, Li Y, Menolfi D, Zhou H, Lu C, Zha S, Goff SP, Zhang Z. Asymmetric distribution of parental H3K9me3 in S phase silences L1 elements. Nature 2023; 623:643-651. [PMID: 37938774 PMCID: PMC11034792 DOI: 10.1038/s41586-023-06711-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/04/2023] [Indexed: 11/08/2023]
Abstract
In eukaryotes, repetitive DNA sequences are transcriptionally silenced through histone H3 lysine 9 trimethylation (H3K9me3). Loss of silencing of the repeat elements leads to genome instability and human diseases, including cancer and ageing1-3. Although the role of H3K9me3 in the establishment and maintenance of heterochromatin silencing has been extensively studied4-6, the pattern and mechanism that underlie the partitioning of parental H3K9me3 at replicating DNA strands are unknown. Here we report that H3K9me3 is preferentially transferred onto the leading strands of replication forks, which occurs predominantly at long interspersed nuclear element (LINE) retrotransposons (also known as LINE-1s or L1s) that are theoretically transcribed in the head-on direction with replication fork movement. Mechanistically, the human silencing hub (HUSH) complex interacts with the leading-strand DNA polymerase Pol ε and contributes to the asymmetric segregation of H3K9me3. Cells deficient in Pol ε subunits (POLE3 and POLE4) or the HUSH complex (MPP8 and TASOR) show compromised H3K9me3 asymmetry and increased LINE expression. Similar results were obtained in cells expressing a MPP8 mutant defective in H3K9me3 binding and in TASOR mutants with reduced interactions with Pol ε. These results reveal an unexpected mechanism whereby the HUSH complex functions with Pol ε to promote asymmetric H3K9me3 distribution at head-on LINEs to suppress their expression in S phase.
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Affiliation(s)
- Zhiming Li
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Shoufu Duan
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Xu Hua
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Xiaowei Xu
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Yinglu Li
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Demis Menolfi
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
| | - Hui Zhou
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Chao Lu
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Departments of Pathology and Cell Biology, Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephen P Goff
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Departments of Biochemistry and Molecular Biophysics, Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Zhiguo Zhang
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA.
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA.
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Bai G, Endres T, Kühbacher U, Greer BH, Peacock EM, Crossley MP, Sathirachinda A, Cortez D, Eichman BF, Cimprich KA. HLTF Prevents G4 Accumulation and Promotes G4-induced Fork Slowing to Maintain Genome Stability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.27.563641. [PMID: 37961428 PMCID: PMC10634870 DOI: 10.1101/2023.10.27.563641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
G-quadruplexes (G4s) form throughout the genome and influence important cellular processes, but their deregulation can challenge DNA replication fork progression and threaten genome stability. Here, we demonstrate an unexpected, dual role for the dsDNA translocase HLTF in G4 metabolism. First, we find that HLTF is enriched at G4s in the human genome and suppresses G4 accumulation throughout the cell cycle using its ATPase activity. This function of HLTF affects telomere maintenance by restricting alternative lengthening of telomeres, a process stimulated by G4s. We also show that HLTF and MSH2, a mismatch repair factor that binds G4s, act in independent pathways to suppress G4s and to promote resistance to G4 stabilization. In a second, distinct role, HLTF restrains DNA synthesis upon G4 stabilization by suppressing PrimPol-dependent repriming. Together, the dual functions of HLTF in the G4 response prevent DNA damage and potentially mutagenic replication to safeguard genome stability.
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