1
|
Chaudhuri A, Paul S, Banerjea M, Das B. Polyadenylated versions of small non-coding RNAs in Saccharomyces cerevisiae are degraded by Rrp6p/Rrp47p independent of the core nuclear exosome. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:155-186. [PMID: 38783922 PMCID: PMC11115967 DOI: 10.15698/mic2024.05.823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/03/2024] [Accepted: 03/05/2024] [Indexed: 05/25/2024]
Abstract
In Saccharomyces cerevisiae, polyadenylated forms of mature (and not precursor) small non-coding RNAs (sncRNAs) those fail to undergo proper 3'-end maturation are subject to an active degradation by Rrp6p and Rrp47p, which does not require the involvement of core exosome and TRAMP components. In agreement with this finding, Rrp6p/Rrp47p is demonstrated to exist as an exosome-independent complex, which preferentially associates with mature polyadenylated forms of these sncRNAs. Consistent with this observation, a C-terminally truncated version of Rrp6p (Rrp6p-ΔC2) lacking physical association with the core nuclear exosome supports their decay just like its full-length version. Polyadenylation is catalyzed by both the canonical and non-canonical poly(A) polymerases, Pap1p and Trf4p. Analysis of the polyadenylation profiles in WT and rrp6-Δ strains revealed that the majority of the polyadenylation sites correspond to either one to three nucleotides upstream or downstream of their mature ends and their poly(A) tails ranges from 10-15 adenylate residues. Most interestingly, the accumulated polyadenylated snRNAs are functional in the rrp6-Δ strain and are assembled into spliceosomes. Thus, Rrp6p-Rrp47p defines a core nuclear exosome-independent novel RNA turnover system in baker's yeast targeting imperfectly processed polyadenylated sncRNAs that accumulate in the absence of Rrp6p.
Collapse
Affiliation(s)
- Anusha Chaudhuri
- Present Position: Zentrum fǜr Molekulare, Medizin, Institut fǜr Kardiovaskuläre Regeneration, Haus 25B, Goethe-Universität, Theodor-Stern-Kai 7, Universitätsklinikum, 60590 Frankfurt am Main, Germany
| | - Soumita Paul
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
| | - Mayukh Banerjea
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
| |
Collapse
|
2
|
Pfannenstein J, Tyryshkin M, Gulden ME, Doud EH, Mosley AL, Reese JC. Characterization of BioID tagging systems in budding yeast and exploring the interactome of the Ccr4-Not complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593354. [PMID: 38766143 PMCID: PMC11100836 DOI: 10.1101/2024.05.09.593354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The modified E. coli biotin ligase BirA* was the first developed for proximity labeling of proteins (BioID). However, it has low activity at temperatures below 37°C, which reduces its effectiveness in organisms growing at lower temperatures, such as budding yeast. Multiple derivatives of the enzymes have been engineered, but a comparison of these variations of biotin ligases has not been reported in Saccharomyces cerevisiae. Here, we designed a suite of vectors to compare the activities of biotin ligase enzymes in yeast. We found that the newer TurboID versions were the most effective at labeling proteins, but they displayed low constitutive activity from biotin contained in the culture medium. We describe a simple strategy to express free BioID enzymes in cells that can be used as an appropriate control in BioID studies to account for the promiscuous labeling of proteins caused by random interactions between bait-BioID enzymes in cells. We also describe chemically-induced BioID systems exploiting the rapamycin-stabilized FRB-FKBP interaction. Finally, we used the TurboID version of the enzyme to explore the interactome of different subunits of the Ccr4-Not gene regulatory complex. We find that Ccr4-Not predominantly labeled cytoplasmic mRNA regulators, consistent with its function in mRNA decay and translation quality control in this cell compartment.
Collapse
|
3
|
Garrido-Godino AI, Gupta I, Pelechano V, Navarro F. RNA Pol II Assembly Affects ncRNA Expression. Int J Mol Sci 2023; 25:507. [PMID: 38203678 PMCID: PMC10778713 DOI: 10.3390/ijms25010507] [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: 11/30/2023] [Revised: 12/26/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
RNA pol II assembly occurs in the cytoplasm before translocation of the enzyme to the nucleus. Affecting this assembly influences mRNA transcription in the nucleus and mRNA decay in the cytoplasm. However, very little is known about the consequences on ncRNA synthesis. In this work, we show that impairment of RNA pol II assembly leads to a decrease in cryptic non-coding RNAs (preferentially CUTs and SUTs). This alteration is partially restored upon overcoming the assembly defect. Notably, this drop in ncRNAs is only partially dependent on the nuclear exosome, which suggests a major specific effect of enzyme assembly. Our data also point out a defect in transcription termination, which leads us to propose that CTD phosphatase Rtr1 could be involved in this process.
Collapse
Affiliation(s)
- Ana I. Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain;
| | - Ishaan Gupta
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany;
| | - Vicent Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 65 Solna, Sweden
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain;
- Instituto Universitario de Investigación en Olivar y Aceites de Oliva (INUO), Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
| |
Collapse
|
4
|
Ma L, Wang L, Gao M, Zhang X, Zhao X, Xie D, Zhang J, Wang Z, Hou L, Zeng F. Rtr1 is required for Rpb1-Rpb2 assembly of RNAPII and prevents their cytoplasmic clump formation. FASEB J 2022; 36:e22585. [PMID: 36190433 DOI: 10.1096/fj.202200698rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/03/2022] [Accepted: 09/20/2022] [Indexed: 11/11/2022]
Abstract
RNA polymerase II (RNAPII) is an essential machinery for catalyzing mRNA synthesis and controlling cell fate in eukaryotes. Although the structure and function of RNAPII have been relatively defined, the molecular mechanism of its assembly process is not clear. The identification and functional analysis of assembly factors will provide new understanding to transcription regulation. In this study, we identify that RTR1, a known transcription regulator, is a new multicopy genetic suppressor of mutants of assembly factors Gpn3, Gpn2, and Rba50. We demonstrate that Rtr1 is directly required to assemble the two largest subunits of RNAPII by coordinating with Gpn3 and Npa3. Deletion of RTR1 leads to cytoplasmic clumping of RNAPII subunit and multiple copies of RTR1 can inhibit the formation of cytoplasmic clump of RNAPII subunit in gpn3-9 mutant, indicating a new layer function of Rtr1 in checking proper assembly of RNAPII. In addition, we find that disrupted activity of Rtr1 phosphatase does not trigger the formation of cytoplasmic clump of RNAPII subunit in a catalytically inactive mutant of RTR1. Based on these results, we conclude that Rtr1 cooperates with Gpn3 and Npa3 to assemble RNAPII core.
Collapse
Affiliation(s)
- Lujie Ma
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Le Wang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Mengdi Gao
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xinjie Zhang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xiangdong Zhao
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Debao Xie
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Jing Zhang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Zhen Wang
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Science & Technology, Hebei Agricultural University, Cangzhou, China
| | - Lifeng Hou
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Fanli Zeng
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Life Sciences, Hebei Agricultural University, Baoding, China
| |
Collapse
|
5
|
RPAP2 regulates a transcription initiation checkpoint by inhibiting assembly of pre-initiation complex. Cell Rep 2022; 39:110732. [PMID: 35476980 DOI: 10.1016/j.celrep.2022.110732] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/31/2021] [Accepted: 04/02/2022] [Indexed: 11/21/2022] Open
Abstract
RNA polymerase II (Pol II)-mediated transcription in metazoans requires precise regulation. RNA Pol II-associated protein 2 (RPAP2) was previously identified to transport Pol II from cytoplasm to nucleus and dephosphorylates Pol II C-terminal domain (CTD). Here, we show that RPAP2 binds hypo-/hyper-phosphorylated Pol II with undetectable phosphatase activity. The structure of RPAP2-Pol II shows mutually exclusive assembly of RPAP2-Pol II and pre-initiation complex (PIC) due to three steric clashes. RPAP2 prevents and disrupts Pol II-TFIIF interaction and impairs in vitro transcription initiation, suggesting a function in inhibiting PIC assembly. Loss of RPAP2 in cells leads to global accumulation of TFIIF and Pol II at promoters, indicating a critical role of RPAP2 in inhibiting PIC assembly independent of its putative phosphatase activity. Our study indicates that RPAP2 functions as a gatekeeper to inhibit PIC assembly and transcription initiation and suggests a transcription checkpoint.
Collapse
|
6
|
Garrido-Godino AI, Cuevas-Bermúdez A, Gutiérrez-Santiago F, Mota-Trujillo MDC, Navarro F. The Association of Rpb4 with RNA Polymerase II Depends on CTD Ser5P Phosphatase Rtr1 and Influences mRNA Decay in Saccharomyces cerevisiae. Int J Mol Sci 2022; 23:ijms23042002. [PMID: 35216121 PMCID: PMC8875030 DOI: 10.3390/ijms23042002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 02/04/2023] Open
Abstract
Rtr1 is an RNA polymerase II (RNA pol II) CTD-phosphatase that influences gene expression during the transition from transcription initiation to elongation and during transcription termination. Rtr1 interacts with the RNA pol II and this interaction depends on the phosphorylation state of the CTD of Rpb1, which may influence dissociation of the heterodimer Rpb4/7 during transcription. In addition, Rtr1 was proposed as an RNA pol II import factor in RNA pol II biogenesis and participates in mRNA decay by autoregulating the turnover of its own mRNA. Our work shows that Rtr1 acts in RNA pol II assembly by mediating the Rpb4/7 association with the rest of the enzyme. RTR1 deletion alters RNA pol II assembly and increases the amount of RNA pol II associated with the chromatin that lacks Rpb4, decreasing Rpb4-mRNA imprinting and, consequently, increasing mRNA stability. Thus, Rtr1 interplays RNA pol II biogenesis and mRNA decay regulation. Our data also indicate that Rtr1 mediates mRNA decay regulation more broadly than previously proposed by cooperating with Rpb4. Interestingly, our data include new layers in the mechanisms of gene regulation and in the crosstalk between mRNA synthesis and decay by demonstrating how the association of Rpb4/7 to the RNA pol II influences mRNA decay.
Collapse
Affiliation(s)
- Ana I. Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Abel Cuevas-Bermúdez
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Francisco Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Maria del Carmen Mota-Trujillo
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
- Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
- Correspondence: ; Tel.: +34-953-212-771; Fax: +34-953-211-875
| |
Collapse
|
7
|
Cheon Y, Han S, Kim T, Hwang D, Lee D. The chromatin remodeler Ino80 mediates RNAPII pausing site determination. Genome Biol 2021; 22:294. [PMID: 34663418 PMCID: PMC8524862 DOI: 10.1186/s13059-021-02500-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/15/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Promoter-proximal pausing of RNA polymerase II (RNAPII) is a critical step for the precise regulation of gene expression. Despite the apparent close relationship between promoter-proximal pausing and nucleosome, the role of chromatin remodeler governing this step has mainly remained elusive. RESULTS Here, we report highly confined RNAPII enrichments downstream of the transcriptional start site in Saccharomyces cerevisiae using PRO-seq experiments. This non-uniform distribution of RNAPII exhibits both similar and different characteristics with promoter-proximal pausing in Schizosaccharomyces pombe and metazoans. Interestingly, we find that Ino80p knockdown causes a significant upstream transition of promoter-proximal RNAPII for a subset of genes, relocating RNAPII from the main pausing site to the alternative pausing site. The proper positioning of RNAPII is largely dependent on nucleosome context. We reveal that the alternative pausing site is closely associated with the + 1 nucleosome, and nucleosome architecture around the main pausing site of these genes is highly phased. In addition, Ino80p knockdown results in an increase in fuzziness and a decrease in stability of the + 1 nucleosome. Furthermore, the loss of INO80 also leads to the shift of promoter-proximal RNAPII toward the alternative pausing site in mouse embryonic stem cells. CONCLUSIONS Based on our collective results, we hypothesize that the highly conserved chromatin remodeler Ino80p is essential in establishing intact RNAPII pausing during early transcription elongation in various organisms, from budding yeast to mouse.
Collapse
Affiliation(s)
- Youngseo Cheon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Sungwook Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Taemook Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Daehee Hwang
- School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
| |
Collapse
|
8
|
Peck Justice SA, McCracken NA, Victorino JF, Qi GD, Wijeratne AB, Mosley AL. Boosting Detection of Low-Abundance Proteins in Thermal Proteome Profiling Experiments by Addition of an Isobaric Trigger Channel to TMT Multiplexes. Anal Chem 2021; 93:7000-7010. [PMID: 33908254 PMCID: PMC8153406 DOI: 10.1021/acs.analchem.1c00012] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
The study of low-abundance
proteins is a challenge to discovery-based
proteomics. Mass spectrometry (MS) applications, such as thermal proteome
profiling (TPP), face specific challenges in the detection of the
whole proteome as a consequence of the use of nondenaturing extraction
buffers. TPP is a powerful method for the study of protein thermal
stability, but quantitative accuracy is highly dependent on consistent
detection. Therefore, TPP can be limited in its amenability to study
low-abundance proteins that tend to have stochastic or poor detection
by MS. To address this challenge, we incorporated an affinity-purified
protein complex sample at submolar concentrations as an isobaric trigger
channel into a mutant TPP (mTPP) workflow to provide reproducible
detection and quantitation of the low-abundance subunits of the cleavage
and polyadenylation factor (CPF) complex. The inclusion of an isobaric
protein complex trigger channel increased detection an average of
40× for previously detected subunits and facilitated detection
of CPF subunits that were previously below the limit of detection.
Importantly, these gains in CPF detection did not cause large changes
in melt temperature (Tm) calculations
for other unrelated proteins in the samples, with a high positive
correlation between Tm estimates in samples
with and without isobaric trigger channel addition. Overall, the incorporation
of an affinity-purified protein complex as an isobaric trigger channel
within a tandem mass tag (TMT) multiplex for mTPP experiments is an
effective and reproducible way to gather thermal profiling data on
proteins that are not readily detected using the original TPP or mTPP
protocols.
Collapse
Affiliation(s)
- Sarah A Peck Justice
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| | - Neil A McCracken
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| | - José F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| | - Guihong D Qi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| | - Aruna B Wijeratne
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
| |
Collapse
|
9
|
Garrido-Godino AI, Gutiérrez-Santiago F, Navarro F. Biogenesis of RNA Polymerases in Yeast. Front Mol Biosci 2021; 8:669300. [PMID: 34026841 PMCID: PMC8136413 DOI: 10.3389/fmolb.2021.669300] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/31/2021] [Indexed: 01/25/2023] Open
Abstract
Eukaryotic RNA polymerases (RNA pols) transcriptional processes have been extensively investigated, and the structural analysis of eukaryotic RNA pols has been explored. However, the global assembly and biogenesis of these heteromultimeric complexes have been narrowly studied. Despite nuclear transcription being carried out by three RNA polymerases in eukaryotes (five in plants) with specificity in the synthesis of different RNA types, the biogenesis process has been proposed to be similar, at least for RNA pol II, to that of bacteria, which contains only one RNA pol. The formation of three different interacting subassembly complexes to conform the complete enzyme in the cytoplasm, prior to its nuclear import, has been assumed. In Saccharomyces cerevisiae, recent studies have examined in depth the biogenesis of RNA polymerases by characterizing some elements involved in the assembly of these multisubunit complexes, some of which are conserved in humans. This study reviews the latest studies governing the mechanisms and proteins described as being involved in the biogenesis of RNA polymerases in yeast.
Collapse
Affiliation(s)
- Ana I Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain
| | | | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain.,Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Jaén, Spain
| |
Collapse
|
10
|
Cossa G, Parua PK, Eilers M, Fisher RP. Protein phosphatases in the RNAPII transcription cycle: erasers, sculptors, gatekeepers, and potential drug targets. Genes Dev 2021; 35:658-676. [PMID: 33888562 PMCID: PMC8091971 DOI: 10.1101/gad.348315.121] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this review, Cossa et al. discuss the current knowledge and outstanding questions about phosphatases in the context of the RNAPII transcription cycle. The transcription cycle of RNA polymerase II (RNAPII) is governed at multiple points by opposing actions of cyclin-dependent kinases (CDKs) and protein phosphatases, in a process with similarities to the cell division cycle. While important roles of the kinases have been established, phosphatases have emerged more slowly as key players in transcription, and large gaps remain in understanding of their precise functions and targets. Much of the earlier work focused on the roles and regulation of sui generis and often atypical phosphatases—FCP1, Rtr1/RPAP2, and SSU72—with seemingly dedicated functions in RNAPII transcription. Decisive roles in the transcription cycle have now been uncovered for members of the major phosphoprotein phosphatase (PPP) family, including PP1, PP2A, and PP4—abundant enzymes with pleiotropic roles in cellular signaling pathways. These phosphatases appear to act principally at the transitions between transcription cycle phases, ensuring fine control of elongation and termination. Much is still unknown, however, about the division of labor among the PPP family members, and their possible regulation by or of the transcriptional kinases. CDKs active in transcription have recently drawn attention as potential therapeutic targets in cancer and other diseases, raising the prospect that the phosphatases might also present opportunities for new drug development. Here we review the current knowledge and outstanding questions about phosphatases in the context of the RNAPII transcription cycle.
Collapse
Affiliation(s)
- Giacomo Cossa
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Pabitra K Parua
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Martin Eilers
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Robert P Fisher
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| |
Collapse
|
11
|
Calvo O. RNA polymerase II phosphorylation and gene looping: new roles for the Rpb4/7 heterodimer in regulating gene expression. Curr Genet 2020; 66:927-937. [PMID: 32508001 DOI: 10.1007/s00294-020-01084-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/22/2022]
Abstract
In eukaryotes, cellular RNAs are produced by three nuclear RNA polymerases (RNAPI, II, and III), which are multisubunit complexes. They share structural and functional features, although they are specialized in the synthesis of specific RNAs. RNAPII transcribes the vast majority of cellular RNAs, including mRNAs and a large number of noncoding RNAs. The structure of RNAPII is highly conserved in all eukaryotes, consisting of 12 subunits (Rpb1-12) organized into five structural modules, among which the Rpb4 and Rpb7 subunits form the stalk. Early studies suggested an accessory role for Rpb4, because is required for specific gene transcription pathways. Far from this initial hypothesis, it is now well established that the Rpb4/7 heterodimer plays much wider roles in gene expression regulation. It participates in nuclear and cytosolic processes ranging from transcription to translation and mRNA degradation in a cyclical process. For this reason, Rpb4/7 is considered a coordinator of gene expression. New functions have been added to the list of stalk functions during transcription, which will be reviewed herein: first, a role in the maintenance of proper RNAPII phosphorylation levels, and second, a role in the establishment of a looped gene architecture in actively transcribed genes.
Collapse
Affiliation(s)
- Olga Calvo
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González 2, Salamanca, 37007, España.
| |
Collapse
|