1
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Pluta AJ, Studniarek C, Murphy S, Norbury CJ. Cyclin-dependent kinases: Masters of the eukaryotic universe. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1816. [PMID: 37718413 PMCID: PMC10909489 DOI: 10.1002/wrna.1816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/21/2023] [Accepted: 08/03/2023] [Indexed: 09/19/2023]
Abstract
A family of structurally related cyclin-dependent protein kinases (CDKs) drives many aspects of eukaryotic cell function. Much of the literature in this area has considered individual members of this family to act primarily either as regulators of the cell cycle, the context in which CDKs were first discovered, or as regulators of transcription. Until recently, CDK7 was the only clear example of a CDK that functions in both processes. However, new data points to several "cell-cycle" CDKs having important roles in transcription and some "transcriptional" CDKs having cell cycle-related targets. For example, novel functions in transcription have been demonstrated for the archetypal cell cycle regulator CDK1. The increasing evidence of the overlap between these two CDK types suggests that they might play a critical role in coordinating the two processes. Here we review the canonical functions of cell-cycle and transcriptional CDKs, and provide an update on how these kinases collaborate to perform important cellular functions. We also provide a brief overview of how dysregulation of CDKs contributes to carcinogenesis, and possible treatment avenues. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Processing > 3' End Processing RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
| | | | - Shona Murphy
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Chris J. Norbury
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
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2
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Kempen RP, Dabas P, Ansari AZ. The Phantom Mark: Enigmatic roles of phospho-Threonine 4 modification of the C-terminal domain of RNA polymerase II. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1771. [PMID: 36606410 PMCID: PMC10323045 DOI: 10.1002/wrna.1771] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/04/2022] [Accepted: 12/07/2022] [Indexed: 01/07/2023]
Abstract
The largest subunit of RNA polymerase II (Pol II) has an unusual carboxyl-terminal domain (CTD). This domain is composed of a tandemly repeating heptapeptide, Y1 S2 P3 T4 S5 P6 S7 , that has multiple roles in regulating Pol II function and processing newly synthesized RNA. Transient phosphorylation of Ser2 and Ser5 of the YS2 PTS5 PS repeat have well-defined roles in recruiting different protein complexes and coordinating sequential steps in gene transcription. As such, these phospho-marks encipher a molecular recognition code, colloquially termed the CTD code. In contrast, the contribution of phospho-Threonine 4 (pThr4/pT4) to the CTD code remains opaque and contentious. Fuelling the debate on the relevance of this mark to gene expression are the findings that replacing Thr4 with a valine or alanine has varied impact on cellular function in different species and independent proteomic analyses disagree on the relative abundance of pThr4 marks. Yet, substitution with negatively charged residues is lethal and even benign mutations selectively disrupt synthesis and 3' processing of distinct sets of coding and non-coding transcripts. Suggestive of non-canonical roles, pThr4 marked Pol II regulates distinct gene classes in a species- and signal-responsive manner. Hinting at undiscovered roles of this elusive mark, multiple signal-responsive kinases phosphorylate Thr4 at target genes. Here, we focus on this under-explored residue and postulate that the pThr4 mark is superimposed on the canonical CTD code to selectively regulate expression of targeted genes without perturbing genome-wide transcriptional processes. This article is categorized under: RNA Processing > 3' End Processing RNA Processing > Processing of Small RNAs RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Ryan P Kempen
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Preeti Dabas
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Aseem Z Ansari
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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3
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Xie Q, Kasahara K, Higo J, Takahashi T. Molecular Mechanisms of Functional Modulation of Transcriptional Coactivator PC4 via Phosphorylation on Its Intrinsically Disordered Region. ACS OMEGA 2023; 8:14572-14582. [PMID: 37125110 PMCID: PMC10134458 DOI: 10.1021/acsomega.3c00364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
To investigate the effects of phosphorylation on the function of the human positive cofactor 4 (PC4), an enhanced molecular dynamics (MD) simulation was performed. The simulation system consists of the N-terminal intrinsic disordered region (IDR) of PC4 and a complex that comprises the C-terminal acidic activation domain of a herpes simplex virion protein 16 (VP16ad) and a homodimer of the C-terminal structured core domain of PC4 (PC4ctd). An earlier report of an experimental study reported that the PC4-VP16ad interaction is modulated by incremental phosphorylation of the IDR. That report also proposed a dynamic model where phosphorylated serine residues of a segment (SEAC) in the IDR contact positively charged residues (lysin and arginine) of another segment (K-rich) in the IDR. This contact formation induced by the phosphorylation results in variation of PC4-VP16ad interaction. However, this contact formation has not yet been measured directly because it is transiently formed and because the SEAC and K-rich segments are unstructured with high flexibility. We performed two simulations to mimic the incremental phosphorylation: the IDR was not phosphorylated in one simulation and only partially phosphorylated in the other. Our simulation results indicate that the phosphorylation weakens the IDR-VP16ad contact considerably with the induction of a compact structure in the IDR. This structure was stabilized by electrostatic interactions between the phosphorylated serine residues of a segment and lysine or arginine residues of another segment in the IDR, but the conformational fluctuation of this compact structure was considerably large. Consequently, the present study supports the experimentally proposed dynamic model. Results of this study can be important for computational elucidation of the functional modulation of PC4.
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Affiliation(s)
- Qilin Xie
- Graduate
School of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Kota Kasahara
- College
of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Junichi Higo
- Graduate
School of Information Science, University
of Hyogo, 7-1-28 minatojima
Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Research
Organization of Science and Technology, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Takuya Takahashi
- College
of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
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4
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Sun X, Wang D, Li W, Gao Q, Tao J, Liu H. Comprehensive analysis of nonsurrounded nucleolus and surrounded nucleolus oocytes on chromatin accessibility using ATAC-seq. Mol Reprod Dev 2023; 90:87-97. [PMID: 36598871 DOI: 10.1002/mrd.23668] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/13/2022] [Accepted: 12/25/2022] [Indexed: 01/05/2023]
Abstract
Mouse germinal vesicle (GV) oocytes are divided into surrounded nucleolus (SN) and nonsurrounded nucleolus (NSN) oocytes based on chromatin morphology. NSN oocytes spontaneously transform into SN oocytes after accumulating enough maternal transcripts. SN oocytes show transcriptional silencing. When oocyte maturation is abnormal or takes place in vitro, NSN oocytes do not go through SN stage before proceeding to MII. Nontransitive oocytes show developmental retardation, a low fertilization rate, and arrest at the two-cell embryo stage in mice. Here, chromatin-binding ribonucleic acid polymerase II (RNAP II) activity, newly synthesized RNA, and chromatin accessibility in GV oocytes were examined. In SN oocytes, RNAP II did not bind to DNA, neo-RNA was not generated in nuclei, and the phosphorylation state of RNAP II did not affect the chromatin-binding activity. The number of accessible genes in SN oocytes was remarkably lower than that in NSN oocytes. The accessibility of different functional genes was also different between the two types of oocytes. Thus, low chromatin accessibility leads to transcriptional silencing in SN oocytes.
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Affiliation(s)
- Xiaofan Sun
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Dayu Wang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Weijian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Qian Gao
- Laboratory Animal Center, College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, China
| | - Jingli Tao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Honglin Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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The Plasmodium falciparum Nuclear Protein Phosphatase NIF4 Is Required for Efficient Merozoite Invasion and Regulates Artemisinin Sensitivity. mBio 2022; 13:e0189722. [PMID: 35938722 PMCID: PMC9426563 DOI: 10.1128/mbio.01897-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Artemisinin resistance in Plasmodium falciparum has been associated with a mutation in the NLI-interacting factor-like phosphatase PfNIF4, in addition to the mutations in the Kelch13 protein as the major determinant. We found that PfNIF4 was predominantly expressed at the schizont stage and localized in the nuclei of the parasite. To elucidate the functions of PfNIF4 in P. falciparum, we performed PfNIF4 knockdown (KD) using the inducible ribozyme system. PfNIF4 KD attenuated merozoite invasion and affected gametocytogenesis. PfNIF4 KD parasites also showed significantly increased in vitro susceptibility to artemisinins. Transcriptomic and proteomic analysis revealed that PfNIF4 KD led to the downregulation of gene categories involved in invasion and artemisinin resistance (e.g., mitochondrial function, membrane, and Kelch13 interactome) at the trophozoite and/or schizont stage. Consistent with PfNIF4 being a protein phosphatase, PfNIF4 KD resulted in an overall upregulation of the phosphoproteome of infected erythrocytes. Quantitative phosphoproteomic profiling identified a set of PfNIF4-regulated phosphoproteins with functional similarity to FCP1 substrates, particularly proteins involved in chromatin organization and transcriptional regulation. Specifically, we observed increased phosphorylation of Ser2/5 of the tandem repeats in the C-terminal domain (CTD) of RNA polymerase II (RNAPII) upon PfNIF4 KD. Furthermore, using the TurboID-based proteomic approach, we identified that PfNIF4 interacted with the RNAPII components, AP2-domain transcription factors, and chromatin-modifiers and binders. These findings suggest that PfNIF4 may act as the RNAPII CTD phosphatase, regulating the expression of general and parasite-specific cellular pathways during the blood-stage development.
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6
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Arefian M, Bhagya N, Prasad TSK. Phosphorylation-mediated signalling in flowering: prospects and retrospects of phosphoproteomics in crops. Biol Rev Camb Philos Soc 2021; 96:2164-2191. [PMID: 34047006 DOI: 10.1111/brv.12748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/18/2022]
Abstract
Protein phosphorylation is a major post-translational modification, regulating protein function, stability, and subcellular localization. To date, annotated phosphorylation data are available mainly for model organisms and humans, despite the economic importance of crop species and their large kinomes. Our understanding of the phospho-regulation of flowering in relation to the biology and interaction between the pollen and pistil is still significantly lagging, limiting our knowledge on kinase signalling and its potential applications to crop production. To address this gap, we bring together relevant literature that were previously disconnected to present an overview of the roles of phosphoproteomic signalling pathways in modulating molecular and cellular regulation within specific tissues at different morphological stages of flowering. This review is intended to stimulate research, with the potential to increase crop productivity by providing a platform for novel molecular tools.
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Affiliation(s)
- Mohammad Arefian
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Center, Yenepoya (Deemed to be University), Mangalore, 575018, India
| | - N Bhagya
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Center, Yenepoya (Deemed to be University), Mangalore, 575018, India
| | - T S Keshava Prasad
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Center, Yenepoya (Deemed to be University), Mangalore, 575018, India
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7
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Łukasik P, Załuski M, Gutowska I. Cyclin-Dependent Kinases (CDK) and Their Role in Diseases Development-Review. Int J Mol Sci 2021; 22:ijms22062935. [PMID: 33805800 PMCID: PMC7998717 DOI: 10.3390/ijms22062935] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are involved in many crucial processes, such as cell cycle and transcription, as well as communication, metabolism, and apoptosis. The kinases are organized in a pathway to ensure that, during cell division, each cell accurately replicates its DNA, and ensure its segregation equally between the two daughter cells. Deregulation of any of the stages of the cell cycle or transcription leads to apoptosis but, if uncorrected, can result in a series of diseases, such as cancer, neurodegenerative diseases (Alzheimer’s or Parkinson’s disease), and stroke. This review presents the current state of knowledge about the characteristics of cyclin-dependent kinases as potential pharmacological targets.
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Affiliation(s)
- Paweł Łukasik
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Michał Załuski
- Department of Pharmaceutical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
| | - Izabela Gutowska
- Department of Medical Chemistry, Pomeranian Medical University in Szczecin, Powstancow Wlkp. 72 Av., 70-111 Szczecin, Poland;
- Correspondence:
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8
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Song Y, Hu G, Jia J, Yao M, Wang X, Lu W, Hutchins AP, Chen J, Ozato K, Yao H. DNA Damage Induces Dynamic Associations of BRD4/P-TEFb With Chromatin and Modulates Gene Transcription in a BRD4-Dependent and -Independent Manner. Front Mol Biosci 2020; 7:618088. [PMID: 33344510 PMCID: PMC7746802 DOI: 10.3389/fmolb.2020.618088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
The bromodomain-containing protein BRD4 has been thought to transmit epigenetic information across cell divisions by binding to both mitotic chromosomes and interphase chromatin. UV-released BRD4 mediates the recruitment of active P-TEFb to the promoter, which enhances transcriptional elongation. However, the dynamic associations between BRD4 and P-TEFb and BRD4-mediated gene regulation after UV stress are largely unknown. In this study, we found that BRD4 dissociates from chromatin within 30 min after UV treatment and thereafter recruits chromatin. However, P-TEFb binds tightly to chromatin right after UV treatment, suggesting that no interactions occur between BRD4 and P-TEFb within 30 min after UV stress. BRD4 knockdown changes the distribution of P-TEFb among nuclear soluble and chromatin and downregulates the elongation activity of RNA polymerase II. Inhibition of JNK kinase but not other MAP kinases impedes the interactions between BRD4 and P-TEFb. RNA-seq and ChIP assays indicate that BRD4 both positively and negatively regulates gene transcription in cells treated with UV stress. These results reveal previously unrecognized dynamics of BRD4 and P-TEFb after UV stress and regulation of gene transcription by BRD4 acting as either activator or repressor in a context-dependent manner.
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Affiliation(s)
- Yawei Song
- School of Life Sciences, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Gongcheng Hu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Jinping Jia
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Mingze Yao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Xiaoshan Wang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Wenliang Lu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Andrew P Hutchins
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Jiekai Chen
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Keiko Ozato
- Division of Developmental Biology, National Institute of Child Health and Human Development, Bethesda, MD, United States
| | - Hongjie Yao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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9
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Antifungal Agent 4-AN Changes the Genome-Wide Expression Profile, Downregulates Virulence-Associated Genes and Induces Necrosis in Candida albicans Cells. Molecules 2020; 25:molecules25122928. [PMID: 32630522 PMCID: PMC7356344 DOI: 10.3390/molecules25122928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/19/2020] [Accepted: 06/24/2020] [Indexed: 11/17/2022] Open
Abstract
In the light of the increasing occurrence of antifungal resistance, there is an urgent need to search for new therapeutic strategies to overcome this phenomenon. One of the applied approaches is the synthesis of small-molecule compounds showing antifungal properties. Here we present a continuation of the research on the recently discovered anti-Candida albicans agent 4-AN. Using next generation sequencing and transcriptional analysis, we revealed that the treatment of C. albicans with 4-AN can change the expression profile of a large number of genes. The highest upregulation was observed in the case of genes involved in cell stress, while the highest downregulation was shown for genes coding sugar transporters. Real-time PCR analysis revealed 4-AN mediated reduction of the relative expression of genes engaged in fungal virulence (ALS1, ALS3, BCR1, CPH1, ECE1, EFG1, HWP1, HYR1 and SAP1). The determination of the fractional inhibitory concentration index (FICI) showed that the combination of 4-AN with amphotericin B is synergistic. Finally, flow cytometry analysis revealed that the compound induces mainly necrosis in C. albicans cells.
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10
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Loyer P, Trembley JH. Roles of CDK/Cyclin complexes in transcription and pre-mRNA splicing: Cyclins L and CDK11 at the cross-roads of cell cycle and regulation of gene expression. Semin Cell Dev Biol 2020; 107:36-45. [PMID: 32446654 DOI: 10.1016/j.semcdb.2020.04.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 12/18/2022]
Abstract
Cyclin Dependent Kinases (CDKs) represent a large family of serine/threonine protein kinases that become active upon binding to a Cyclin regulatory partner. CDK/cyclin complexes recently identified, as well as "canonical" CDK/Cyclin complexes regulating cell cycle, are implicated in the regulation of gene expression via the phosphorylation of key components of the transcription and pre-mRNA processing machineries. In this review, we summarize the role of CDK/cyclin-dependent phosphorylation in the regulation of transcription and RNA splicing and highlight recent findings that indicate the involvement of CDK11/cyclin L complexes at the cross-roads of cell cycle, transcription and RNA splicing. Finally, we discuss the potential of CDK11 and Cyclins L as therapeutic targets in cancer.
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Affiliation(s)
- Pascal Loyer
- INSERM, INRAE, Univ Rennes, NuMeCan, Nutrition Metabolisms and Cancer, Rennes, France.
| | - Janeen H Trembley
- Research Service, Minneapolis VA Health Care System, Minneapolis, MN 55417, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
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11
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Zhang Y, Wang Y, Xu Q, Zhu J, Lin Y. Molecular and expression characteristics of resistin (RETN) and its effects on the differentiation of intramuscular preadipocyte in goat. Anim Biotechnol 2019; 32:113-120. [PMID: 31516062 DOI: 10.1080/10495398.2019.1664564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Resistin (RETN) is a hormone secreted by adipocytes, which plays an important role in glucose and lipid metabolism. The aim of this study is to clone and obtain the full length open reading frame (ORF) of goat RETN gene sequence, and to reveal its molecular and expression characteristics. Simultaneously, we explore its effect on the differentiation of intramuscular preadipocytes in goat. The full length ORF sequence of goat RETN gene was cloned by RT-PCR technique, and bioinformatics analysis was performed though relevant biological softwares. In this study, the expression of RETN mRNA in goat tissues and intramuscular preadipocytes during differentiation was detected by qPCR technique. Furthermore, RNA interference was used to explore the effects of RETN on intramuscular preadipocytes differentiation in goat. The results showed that the cloned goat RETN gene sequence was 428 bp in length, of which the ORF was 330 bp, encoding 109 amino acids. Sequence analysis revealed that it had 12 phosphorylation sites and an O-glycosylation site, and its protein contained a signal peptide sequence. Also, the RETN gene is expressed in goat various analyzed tissues, and the results showed that the expression of RETN gene in lung tissue was higher than that in other analyzed tissues of goat (p < .01). Moreover, the expression level of RETN gene in the goat's intramuscular preadipocytes decreased first and then increased, and reached the highest on the fifth day, which was significantly higher than that of undifferentiated intramuscular preadipocytes (p < .001). After transfecting intramuscular preadipocyte with siRNA, we found that the mRNA level of RETN was significantly down-regulated by 70% and 87% (p < .01). Oil red O staining results showed that the interference of RETN gene can promote the differentiation of intramuscular preadipocytes. After knockdown of RETN with siRNA, the PPARγ, AP2, C/EBPα, C/EBPβ and SREBP1 genes were significantly up-regulated (p < .01). Thus, it can be inferred that RETN inhibits the differentiation of goat intramuscular preadipocytes, probably through regulating the expression of C/EBPα, C/EBPβ, PPARγ, AP2 and SREBP-1 genes.
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Affiliation(s)
- Yanan Zhang
- School of Life Science and Technology, Southwest Minzu University, Chengdu, Sichuan, China.,Ministry of Education, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Southwest Minzu University, Chengdu, Sichuan, China
| | - Yong Wang
- Ministry of Education, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Southwest Minzu University, Chengdu, Sichuan, China.,Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization Key Laboratory of Sichuan Province, Chengdu, Sichuan, China
| | - Qing Xu
- School of Life Science and Technology, Southwest Minzu University, Chengdu, Sichuan, China.,Ministry of Education, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Southwest Minzu University, Chengdu, Sichuan, China
| | - Jiangjiang Zhu
- Ministry of Education, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Southwest Minzu University, Chengdu, Sichuan, China.,Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization Key Laboratory of Sichuan Province, Chengdu, Sichuan, China
| | - Yaqiu Lin
- School of Life Science and Technology, Southwest Minzu University, Chengdu, Sichuan, China.,Ministry of Education, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Southwest Minzu University, Chengdu, Sichuan, China
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12
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Abstract
Renal cell carcinomas (RCCs) are a diverse set of malignancies that have recently been shown to harbour mutations in a number of chromatin modifier genes - including PBRM1, SETD2, BAP1, KDM5C, KDM6A, and MLL2 - through high-throughput sequencing efforts. Current research focuses on understanding the biological activities that chromatin modifiers employ to suppress tumorigenesis and on developing clinical approaches that take advantage of this knowledge. Unsurprisingly, several common themes unify the functions of these epigenetic modifiers, particularly regulation of histone post-translational modifications and nucleosome organization. Furthermore, chromatin modifiers also govern processes crucial for DNA repair and maintenance of genomic integrity as well as the regulation of splicing and other key processes. Many chromatin modifiers have additional non-canonical roles in cytoskeletal regulation, which further contribute to genomic stability, expanding the repertoire of functions that might be essential in tumorigenesis. Our understanding of how mutations in chromatin modifiers contribute to tumorigenesis in RCC is improving but remains an area of intense investigation. Importantly, elucidating the activities of chromatin modifiers offers intriguing opportunities for the development of new therapeutic interventions in RCC.
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Affiliation(s)
- Aguirre A de Cubas
- Department of Medicine, Division of Hematology and Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - W Kimryn Rathmell
- Department of Medicine, Division of Hematology and Oncology, Vanderbilt University Medical Center, Nashville, TN, USA.
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13
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Kecman T, Kuś K, Heo DH, Duckett K, Birot A, Liberatori S, Mohammed S, Geis-Asteggiante L, Robinson CV, Vasiljeva L. Elongation/Termination Factor Exchange Mediated by PP1 Phosphatase Orchestrates Transcription Termination. Cell Rep 2018; 25:259-269.e5. [PMID: 30282034 PMCID: PMC6180485 DOI: 10.1016/j.celrep.2018.09.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/27/2018] [Accepted: 09/04/2018] [Indexed: 11/20/2022] Open
Abstract
Termination of RNA polymerase II (Pol II) transcription is a key step that is important for 3' end formation of functional mRNA, mRNA release, and Pol II recycling. Even so, the underlying termination mechanism is not yet understood. Here, we demonstrate that the conserved and essential termination factor Seb1 is found on Pol II near the end of the RNA exit channel and the Rpb4/7 stalk. Furthermore, the Seb1 interaction surface with Pol II largely overlaps with that of the elongation factor Spt5. Notably, Seb1 co-transcriptional recruitment is dependent on Spt5 dephosphorylation by the conserved PP1 phosphatase Dis2, which also dephosphorylates threonine 4 within the Pol II heptad repeated C-terminal domain. We propose that Dis2 orchestrates the transition from elongation to termination phase during the transcription cycle by mediating elongation to termination factor exchange and dephosphorylation of Pol II C-terminal domain.
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Affiliation(s)
- Tea Kecman
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Krzysztof Kuś
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Dong-Hyuk Heo
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Katie Duckett
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Adrien Birot
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK; Department of Chemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Lidia Vasiljeva
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
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14
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Ne E, Palstra RJ, Mahmoudi T. Transcription: Insights From the HIV-1 Promoter. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 335:191-243. [DOI: 10.1016/bs.ircmb.2017.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Wittmann S, Renner M, Watts BR, Adams O, Huseyin M, Baejen C, El Omari K, Kilchert C, Heo DH, Kecman T, Cramer P, Grimes JM, Vasiljeva L. The conserved protein Seb1 drives transcription termination by binding RNA polymerase II and nascent RNA. Nat Commun 2017; 8:14861. [PMID: 28367989 PMCID: PMC5382271 DOI: 10.1038/ncomms14861] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 02/05/2017] [Indexed: 11/09/2022] Open
Abstract
Termination of RNA polymerase II (Pol II) transcription is an important step in the transcription cycle, which involves the dislodgement of polymerase from DNA, leading to release of a functional transcript. Recent studies have identified the key players required for this process and showed that a common feature of these proteins is a conserved domain that interacts with the phosphorylated C-terminus of Pol II (CTD-interacting domain, CID). However, the mechanism by which transcription termination is achieved is not understood. Using genome-wide methods, here we show that the fission yeast CID-protein Seb1 is essential for termination of protein-coding and non-coding genes through interaction with S2-phosphorylated Pol II and nascent RNA. Furthermore, we present the crystal structures of the Seb1 CTD- and RNA-binding modules. Unexpectedly, the latter reveals an intertwined two-domain arrangement of a canonical RRM and second domain. These results provide important insights into the mechanism underlying eukaryotic transcription termination.
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Affiliation(s)
- Sina Wittmann
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Max Renner
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Beth R Watts
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Oliver Adams
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Miles Huseyin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Carlo Baejen
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Kamel El Omari
- Diamond Light Source Ltd, Harwell Science &Innovation Campus, Didcot OX11 0DE, UK
| | - Cornelia Kilchert
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Dong-Hyuk Heo
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Tea Kecman
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Jonathan M Grimes
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.,Diamond Light Source Ltd, Harwell Science &Innovation Campus, Didcot OX11 0DE, UK
| | - Lidia Vasiljeva
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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16
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Pinhero R, Yankulov K. Expression and Purification of Recombinant CDKs: CDK7, CDK8, and CDK9. Methods Mol Biol 2016; 1336:13-28. [PMID: 26231705 DOI: 10.1007/978-1-4939-2926-9_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cyclin-dependent kinases have established roles in the regulation of cell cycle, in gene expression and in cell differentiation. Many of these kinases have been considered as drug targets and numerous efforts have been made to develop specific and potent inhibitors against them. The first step in all of these attempts and in many other biochemical analyses is the production of highly purified and reliable kinase, most frequently in a recombinant form. In this chapter we describe our experience in the cloning, expression, and purification of CDKs using CDK7/CycH, CDK8/CycC, and CDK9/CycT1 as an example.
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Affiliation(s)
- Reena Pinhero
- Department of Molecular Biology and Genetics, University of Guelph, 50 Stone Road East, Guelph, ON, Canada, N1G 2W1
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17
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Sahu G, Farley K, El-Hage N, Aiamkitsumrit B, Fassnacht R, Kashanchi F, Ochem A, Simon GL, Karn J, Hauser KF, Tyagi M. Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR. Virology 2015; 483:185-202. [PMID: 25980739 DOI: 10.1016/j.virol.2015.03.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication.
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Affiliation(s)
- Geetaram Sahu
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States
| | - Kalamo Farley
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States
| | - Nazira El-Hage
- Virginia Commonwealth University, Richmond, VA, United States
| | - Benjamas Aiamkitsumrit
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States
| | - Ryan Fassnacht
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States
| | | | - Alex Ochem
- ICGEB, Wernher and Beit Building, Anzio Road, Observatory, 7925 Cape Town, South Africa
| | - Gary L Simon
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States
| | - Jonathan Karn
- Case Western Reserve University, Cleveland, OH, United States
| | - Kurt F Hauser
- Virginia Commonwealth University, Richmond, VA, United States
| | - Mudit Tyagi
- Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC, United States; Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC 20037, United States.
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18
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Kołowerzo-Lubnau A, Niedojadło J, Świdziński M, Bednarska-Kozakiewicz E, Smoliński DJ. Transcriptional activity in diplotene larch microsporocytes, with emphasis on the diffuse stage. PLoS One 2015; 10:e0117337. [PMID: 25671569 PMCID: PMC4324999 DOI: 10.1371/journal.pone.0117337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 12/22/2014] [Indexed: 12/22/2022] Open
Abstract
Manuscript provides insights into the biology of long-lived plants, different from Arabidopsis, tomato or grass species that are widely studied. In the European larch the diplotene stage lasts approximately 5 months and it is possible to divide it into several substages and to observe each of them in details. The diplotene stage is a period of intensive microsporocyte growth associated with the synthesis and accumulation of different RNA and proteins. Larch microsporocytes display changes in chromatin morphology during this stage, alternating between 4 short stages of chromatin condensation (contraction) and 5 longer diffusion (relaxation) stages. The occurrence of a diplotene diffusion stage has been observed in many plant species. Interestingly, they have also been observed during spermiogenesis and oogenesis in animals. The aim of this study was to examine whether chromatin relaxation during the diplotene is accompanied by the synthesis and maturation of mRNA. The results reveal a correlation between the diffusion and chromatin decondensation, transcriptional activity. We also found decreasing amount of poly(A) mRNA synthesis in the consecutive diffusion stages. During the early diffusion stages, mRNA is intensively synthesized. In the nuclei large amounts of RNA polymerase II, and high levels of snRNPs were observed. In the late diffusion stages, the synthesized mRNA is not directly subjected to translation but it is stored in the nucleus, and later transported to the cytoplasm and translated. In the last diffusion stage, the level of poly(A) RNA is low, but that of splicing factors is still high. It appears that the mRNA synthesized in early stages is used during the diplotene stage and is not transmitted to dyad and tetrads. In contrast, splicing factors accumulate and are most likely transmitted to the dyad and tetrads, where they are used after the resumption of intense transcription. Similar meiotic process were observed during oogenesis in animals. This indicates the existence of an evolutionarily conserved mechanism of chromatin-based regulation of gene expression during meiotic prophase I.
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Affiliation(s)
- Agnieszka Kołowerzo-Lubnau
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
- * E-mail: (AKL); (DJS)
| | - Janusz Niedojadło
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Michał Świdziński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Elżbieta Bednarska-Kozakiewicz
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Dariusz J. Smoliński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
- * E-mail: (AKL); (DJS)
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19
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20
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Zhang Y, Charvat RA, Kim SK, O'Callaghan DJ. The EHV-1 UL4 protein that tempers viral gene expression interacts with cellular transcription factors. Virology 2014; 449:25-34. [PMID: 24418534 DOI: 10.1016/j.virol.2013.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 03/18/2013] [Accepted: 11/04/2013] [Indexed: 10/26/2022]
Abstract
The UL4 gene is conserved within the genome of defective interfering particles of equine herpesvirus type 1 (EHV-1) that mediate persistent infection. Here, we show that the UL4 protein inhibits EHV-1 reporter gene expression by decreasing the level of transcribed mRNA. The UL4 protein did not bind any gene class of EHV-1 promoters in electromobility or chromatin immunoprecipitation assays, but directly interacted with the TATA box-binding protein (TBP) and the carboxy-terminal domain of RNA polymerase II both in vitro (GST-pulldown assays) and in infected cells (coimmunoprecipitation analyses). Microarray analyses of the expression of the 78 EHV-1 genes revealed that viral late genes important for virion assembly displayed enhanced expression in cells infected with UL4-null virus as compared to wild-type or UL4-restored EHV-1. Quantitative PCR analyses showed that viral DNA replication was not retarded in cells infected with the UL4-null virus as compared to wild-type EHV-1.
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Affiliation(s)
- Yunfei Zhang
- Center for Molecular and Tumor Virology, Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
| | - Robert A Charvat
- Center for Molecular and Tumor Virology, Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
| | - Seong K Kim
- Center for Molecular and Tumor Virology, Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
| | - Dennis J O'Callaghan
- Center for Molecular and Tumor Virology, Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
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21
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Aristizabal MJ, Negri GL, Benschop JJ, Holstege FCP, Krogan NJ, Kobor MS. High-throughput genetic and gene expression analysis of the RNAPII-CTD reveals unexpected connections to SRB10/CDK8. PLoS Genet 2013; 9:e1003758. [PMID: 24009531 PMCID: PMC3757075 DOI: 10.1371/journal.pgen.1003758] [Citation(s) in RCA: 18] [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: 01/28/2013] [Accepted: 07/15/2013] [Indexed: 12/21/2022] Open
Abstract
The C-terminal domain (CTD) of RNA polymerase II (RNAPII) is composed of heptapeptide repeats, which play a key regulatory role in gene expression. Using genetic interaction, chromatin immunoprecipitation followed by microarrays (ChIP-on-chip) and mRNA expression analysis, we found that truncating the CTD resulted in distinct changes to cellular function. Truncating the CTD altered RNAPII occupancy, leading to not only decreases, but also increases in mRNA levels. The latter were largely mediated by promoter elements and in part were linked to the transcription factor Rpn4. The mediator subunit Cdk8 was enriched at promoters of these genes, and its removal not only restored normal mRNA and RNAPII occupancy levels, but also reduced the abnormally high cellular amounts of Rpn4. This suggested a positive role of Cdk8 in relationship to RNAPII, which contrasted with the observed negative role at the activated INO1 gene. Here, loss of CDK8 suppressed the reduced mRNA expression and RNAPII occupancy levels of CTD truncation mutants.
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Affiliation(s)
- Maria J. Aristizabal
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gian Luca Negri
- School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Joris J. Benschop
- Molecular Cancer Research, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Frank C. P. Holstege
- Molecular Cancer Research, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Nevan J. Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California, United States of America
| | - Michael S. Kobor
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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22
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Wu Q, Kang H, Tian C, Huang Q, Zhu R. Binding Mechanism of Inhibitors to CDK5/p25 Complex: Free Energy Calculation and Ranking Aggregation Analysis. Mol Inform 2013; 32:251-60. [DOI: 10.1002/minf.201200139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 01/17/2013] [Indexed: 11/11/2022]
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23
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Guo L, Wu WJ, Liu LD, Wang LC, Zhang Y, Wu LQ, Guan Y, Li QH. Herpes simplex virus 1 ICP22 inhibits the transcription of viral gene promoters by binding to and blocking the recruitment of P-TEFb. PLoS One 2012; 7:e45749. [PMID: 23029222 PMCID: PMC3454370 DOI: 10.1371/journal.pone.0045749] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/24/2012] [Indexed: 11/18/2022] Open
Abstract
ICP22 is a multifunctional herpes simplex virus 1 (HSV-1) immediate early protein that functions as a general repressor of a subset of cellular and viral promoters in transient expression systems. Although the exact mechanism of repression remains unclear, this protein induces a decrease in RNA polymerase II Serine 2 (RNAPII Ser-2) phosphorylation, which is critical for transcription elongation. To characterize the mechanism of transcriptional repression by ICP22, we established an in vivo transient expression reporter system. We found that ICP22 inhibits transcription of the HSV-1 α, β and γ gene promoters. The viral tegument protein VP16, which plays vital roles in initiation of viral gene expression and viral proliferation, can overcome the inhibitory effect of ICP22 on α-gene transcription. Further immunoprecipitation studies indicated that both ICP22 and VP16 bind to positive transcription elongation factor b (P-TEFb) and form a complex with it in vivo. We extended this to show that P-TEFb regulates transcription of the viral α-gene promoters and affects transcriptional regulation of ICP22 and VP16 on the α-genes. Additionally, ChIP assays demonstrated that ICP22 blocks the recruitment of P-TEFb to the viral promoters, while VP16 reverses this blocking effect by recruiting P-TEFb to the viral α-gene promoters through recognition of the TAATGARAT motif. Taken together, our results suggest that ICP22 interacts with and blocks the recruitment of P-TEFb to viral promoter regions, which inhibits transcription of the viral gene promoters. The transactivator VP16 binds to and induces the recruitment of P-TEFb to viral α-gene promoters, which counteracts the transcriptional repression of ICP22 on α-genes by recruiting p-TEFb to the promoter region.
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Affiliation(s)
- Lei Guo
- Institute of Medical Biology, Chinese Academy of Medicine Science, Peking Union Medical College, Kunming, People's Republic of China
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24
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Juhász I, Villányi Z, Tombácz I, Boros IM. High Fcp1 phosphatase activity contributes to setting an intense transcription rate required in Drosophila nurse and follicular cells for egg production. Gene 2012; 509:60-7. [PMID: 22903034 DOI: 10.1016/j.gene.2012.07.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 11/28/2022]
Abstract
During transcription cycles serine side chains in the carboxyl terminal domain (CTD) of the largest subunit of RNA polymerase II undergo dynamic phosphorylation-de-phosphorylation changes, and the modification status of the CTD serves as a signal for proteins involved in transcription and RNA maturation. We show here that the major CTD de-phosphorylating enzyme Fcp1 is expressed at high levels in germline cells of Drosophila. We used transgene constructs to modify the Fcp1 phosphatase level in Drosophila ovaries and found that high levels of Fcp1 are required for intensive gene expression in nurse cells. On the contrary, low Fcp1 levels might limit the rate of transcription. Fcp1 over-expression results in increased expression of microtubules in nurse cells. Our results show that tightly controlled high level Fcp1 expression in the nurse cells of Drosophila ovaries is required for proper egg maturation.
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Affiliation(s)
- Ildikó Juhász
- Department of Biochemistry and Molecular Biology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
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25
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Smirnova EV, Lakunina VA, Tarassov I, Krasheninnikov IA, Kamenski PA. Noncanonical functions of aminoacyl-tRNA synthetases. BIOCHEMISTRY (MOSCOW) 2012; 77:15-25. [PMID: 22339629 DOI: 10.1134/s0006297912010026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aminoacyl-tRNA synthetases, together with their main function of covalent binding of an amino acid to a corresponding tRNA, also perform many other functions. They take part in regulation of gene transcription, apoptosis, translation, and RNA splicing. Some of them function as cytokines or catalyze different reactions in living cells. Noncanonical functions can be mediated by additional domains of these proteins. On the other hand, some of the noncanonical functions are directly associated with the active center of the aminoacylation reaction. In this review we summarize recent data on the noncanonical functions of aminoacyl-tRNA synthetases and on the mechanisms of their action.
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Affiliation(s)
- E V Smirnova
- Department of Molecular Biology, Lomonosov Moscow State University, Moscow, Russia
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26
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Cyclin-dependent kinases: bridging their structure and function through computations. Future Med Chem 2011; 3:1551-9. [PMID: 21882947 DOI: 10.4155/fmc.11.113] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are one of the most promising target families for drug discovery for several diseases, such as cancer and neurodegenerative disorders. Over the years, structural insights on CDKs have demonstrated high protein plasticity, with several cases where two or more structures of the same protein adopt different conformations. This has generated a great deal of interest in understanding the relationship between CDK structure and function. Here, we highlight how computer simulations have recently contributed in characterizing some key rare and transient events in CDKs, such as the reaction transition state and activation loop movement. Although not yet fully defined, we can now portray the enzymatic mechanism and plasticity of CDKs at high spatial and temporal resolution. These theoretical studies bridge with experiments and highlight structural determinants that could help in designing specific CDK inhibitors.
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27
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Wang Y, Lu JJ, He L, Yu Q. Triptolide (TPL) inhibits global transcription by inducing proteasome-dependent degradation of RNA polymerase II (Pol II). PLoS One 2011; 6:e23993. [PMID: 21931633 PMCID: PMC3172214 DOI: 10.1371/journal.pone.0023993] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 08/03/2011] [Indexed: 11/18/2022] Open
Abstract
Triptolide (TPL), a key biologically active component of the Chinese medicinal herb Tripterygium wilfordii Hook. f., has potent anti-inflammation and anti-cancer activities. Its anti-proliferative and pro-apoptotic effects have been reported to be related to the inhibition of Nuclear Factor κB (NF-κB) and Nuclear Factor of Activated T-cells (NFAT) mediated transcription and suppression of HSP70 expression. The direct targets and precise mechanisms that are responsible for the gene expression inhibition, however, remain unknown. Here, we report that TPL inhibits global gene transcription by inducing proteasome-dependent degradation of the largest subunit of RNA polymerase II (Rpb1) in cancer cells. In the presence of proteosome inhibitor MG132, TPL treatment causes hyperphosphorylation of Rpb1 by activation of upstream protein kinases such as Positive Transcription Elongation Factor b (P-TEFb) in a time and dose dependent manner. Also, we observe that short time incubation of TPL with cancer cells induces DNA damage. In conclusion, we propose a new mechanism of how TPL works in killing cancer. TPL inhibits global transcription in cancer cells by induction of phosphorylation and subsequent proteasome-dependent degradation of Rpb1 resulting in global gene transcription, which may explain the high potency of TPL in killing cancer.
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Affiliation(s)
- Ying Wang
- Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Jin-jian Lu
- Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, People's Republic of China
| | - Li He
- Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Qiang Yu
- Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
- * E-mail:
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28
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Bjarnadottir U, Nielsen JE. Predicting the open conformations of protein kinases using molecular dynamics simulations. Biopolymers 2011; 97:65-72. [PMID: 21858778 DOI: 10.1002/bip.21704] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 08/15/2011] [Indexed: 11/11/2022]
Abstract
Protein kinases (PK) control phosphorylation in eukaryotic cells, and thereby regulate metabolic pathways, cell cycle progression, apoptosis, and transcription. Consequently, there is significant interest in manipulating PK activity and treat diseases by using small-molecule drugs. All PK catalytic domains undergo large conformational changes as a result of substrate binding and phosphorylation. The "closed" state of a PK catalytic domain is the only state able to phosphorylate the target substrate, which makes the two other observed states (the "open" and the "intermediate" states) interesting drug targets. We investigate whether molecular dynamics (MD) simulations starting from the closed state of the catalytic domain of protein kinase A (C-PKA) can be used to produce realistic structures representing the intermediate and/or open conformation of C-PKA, because this would allow for drug docking calculations and drug design using MD snapshots. We perform 36 ten-nanosecond MD simulations starting from the closed conformation [PDB ID: ATP] of C-PKA in various liganded and phosphorylated states. The results show that MD simulations are capable of reproducing the open conformation of C-PKA with good accuracy within 1 ns of simulation as measured by Cα root mean square deviations (RMSDs) and RMSDs of atoms defining the ATP-binding pocket. Importantly, we are able to show that even without knowledge of the structure of the open form of C-PKA, we can identify the MD snapshots resembling the open conformation most using the open structure of a different PK displaying only 23% sequence identity to C-PKA.
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Affiliation(s)
- Una Bjarnadottir
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Sadeh A, Movshovich N, Volokh M, Gheber L, Aharoni A. Fine-tuning of the Msn2/4-mediated yeast stress responses as revealed by systematic deletion of Msn2/4 partners. Mol Biol Cell 2011; 22:3127-38. [PMID: 21757539 PMCID: PMC3164460 DOI: 10.1091/mbc.e10-12-1007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Msn2 and Msn4 transcription factors play a major role in yeast response to a variety of stress conditions. A systematic approach to the identification of Msn2/4 activators or suppressors shows that the majority of the Msn2 protein regulatory network acts to fine-tune its activity following yeast exposure to diverse stress conditions. The Msn2 and Msn4 transcription factors play major roles in the yeast general stress response by mediating the transcription of hundreds of genes. Despite extensive information on Msn2/4–mediated gene expression profiles, much less is known regarding the network of proteins that regulate its activity. Here we describe a systematic approach designed to examine the roles of 35 Msn2/4 partners in regulating Msn2/4 transcriptional activity in the face of four different environmental conditions. Our analysis indicates that single deletions of 26 Msn2/4 partners significantly affect Msn2/4 transcription activity under four different conditions. The low functional redundancy of the Msn2 regulatory network indicates that Msn2/4 activity is finely tuned by many of Msn2/4 partners to provide an optimized stress response through differential activation, nuclear localization, degradation, and chromatin remodeling. Our specific analysis of Msn2 activity showed that a relatively large number of partners act to suppress Msn2 activity under nonstress conditions through independent mechanisms, including cytoplasmic retention, proteosome-mediated Msn2 degradation, and chromatin remodeling. Such negative regulation is crucial to minimize the cost of uncontrolled stress response gene expression and ensures a high growth rate in the absence of stress.
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Affiliation(s)
- Amit Sadeh
- Departments of Life Science, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
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30
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Hollidge BS, Weiss SR, Soldan SS. The role of interferon antagonist, non-structural proteins in the pathogenesis and emergence of arboviruses. Viruses 2011; 3:629-58. [PMID: 21994750 PMCID: PMC3185780 DOI: 10.3390/v3060629] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/04/2011] [Accepted: 05/07/2011] [Indexed: 12/24/2022] Open
Abstract
A myriad of factors favor the emergence and re-emergence of arthropod-borne viruses (arboviruses), including migration, climate change, intensified livestock production, an increasing volume of international trade and transportation, and changes to ecosystems (e.g., deforestation and loss of biodiversity). Consequently, arboviruses are distributed worldwide and represent over 30% of all emerging infectious diseases identified in the past decade. Although some arboviral infections go undetected or are associated with mild, flu-like symptoms, many are important human and veterinary pathogens causing serious illnesses such as arthritis, gastroenteritis, encephalitis and hemorrhagic fever and devastating economic loss as a consequence of lost productivity and high mortality rates among livestock. One of the most consistent molecular features of emerging arboviruses, in addition to their near exclusive use of RNA genomes, is the inclusion of viral, non-structural proteins that act as interferon antagonists. In this review, we describe these interferon antagonists and common strategies that arboviruses use to counter the host innate immune response. In addition, we discuss the complex interplay between host factors and viral determinants that are associated with virus emergence and re-emergence, and identify potential targets for vaccine and anti-viral therapies.
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Affiliation(s)
- Bradley S. Hollidge
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA; E-Mail:
- Neuroscience Graduate Group, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Susan R. Weiss
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA; E-Mail:
| | - Samantha S. Soldan
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-215-898-3502; Fax: +1-215-573-2029
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31
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Liu X, Lam F, Shi S, Fischer PM, Wang S. In vitro antitumor mechanism of a novel cyclin-dependent kinase inhibitor CDKI-83. Invest New Drugs 2011; 30:889-97. [DOI: 10.1007/s10637-011-9641-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 02/01/2011] [Indexed: 11/30/2022]
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Functional characterization of a new member of the Cdk9 family in Aspergillus nidulans. EUKARYOTIC CELL 2010; 9:1901-12. [PMID: 20952582 DOI: 10.1128/ec.00384-09] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cdk9-like kinases in complex with T-type cyclins are essential components of the eukaryotic transcription elongation machinery. The full spectrum of Cdk9/cyclin T targets, as well as the specific consequences of phosphorylations, is still largely undefined. We identify and characterize here a Cdk9 kinase (PtkA) in the filamentous ascomycete Aspergillus nidulans. Deletion of ptkA had a lethal effect in later stages of vegetative growth and completely impeded asexual development. Overexpression of ptkA affected directionality of polarized growth and the initiation of new branching sites. A green fluorescent protein-tagged PtkA version localized inside the nucleus during interphase, supporting a role of PtkA in transcription elongation, as observed in other organisms. We also identified a putative cyclin T homolog, PchA, in the A. nidulans genome and confirmed its interaction with PtkA in vivo. Surprisingly, the Pcl-like cyclin PclA, previously described to be involved in asexual development, was also found to interact with PtkA, indicating a possible role of PtkA in linking transcriptional activity with development and/or morphogenesis in A. nidulans. This is the first report of a Cdk9 kinase interacting with a Pcl-like cyclin, revealing interesting new aspects about the involvement of this Cdk-subfamily in differential gene expression.
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Calderwood SK, Xie Y, Wang X, Khaleque MA, Chou SD, Murshid A, Prince T, Zhang Y. Signal Transduction Pathways Leading to Heat Shock Transcription. ACTA ACUST UNITED AC 2010; 2:13-24. [PMID: 21687820 DOI: 10.4137/sti.s3994] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heat shock proteins (HSP) are essential for intracellular protein folding during stress and protect cells from denaturation and aggregation cascades that can lead to cell death. HSP genes are regulated at the transcriptional level by heat shock transcription factor 1 (HSF1) that is activated by stress and binds to heat shock elements in HSP genes. The activation of HSF1 during heat shock involves conversion from an inert monomer to a DNA binding trimer through a series of intramolecular folding rearrangements. However, the trigger for HSF1 at the molecular level is unclear and hypotheses for this process include reversal of feedback inhibition of HSF1 by molecular chaperones and heat-induced binding to large non-coding RNAs. Heat shock also causes a profound modulation in cell signaling pathways that lead to protein kinase activation and phosphorylation of HSF1 at a number of regulatory serine residues. HSP genes themselves exist in an accessible chromatin conformation already bound to RNA polymerase II. The RNA polymerase II is paused on HSP promoters after transcribing a short RNA sequence proximal to the promoter. Activation by heat shock involves HSF1 binding to the promoter and release of the paused RNA polymerase II followed by further rounds of transcriptional initiation and elongation. HSF1 is thus involved in both initiation and elongation of HSP RNA transcripts. Recent studies indicate important roles for histone modifications on HSP genes during heat shock. Histone modification occurs rapidly after stress and may be involved in promoting nucleosome remodeling on HSP promoters and in the open reading frames of HSP genes. Understanding these processes may be key to evaluating mechanisms of deregulated HSP expression that plays a key role in neurodegeneration and cancer.
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Affiliation(s)
- S K Calderwood
- Division of Molecular and Cellular Radiation Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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34
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Abstract
Although now dogma, the idea that nonvertebrate organisms such as yeast, worms, and flies could inform, and in some cases even revolutionize, our understanding of oncogenesis in humans was not immediately obvious. Aided by the conservative nature of evolution and the persistence of a cohort of devoted researchers, the role of model organisms as a key tool in solving the cancer problem has, however, become widely accepted. In this review, we focus on the nematode Caenorhabditis elegans and its diverse and sometimes surprising contributions to our understanding of the tumorigenic process. Specifically, we discuss findings in the worm that address a well-defined set of processes known to be deregulated in cancer cells including cell cycle progression, growth factor signaling, terminal differentiation, apoptosis, the maintenance of genome stability, and developmental mechanisms relevant to invasion and metastasis.
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Affiliation(s)
- Natalia V. Kirienko
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
| | - Kumaran Mani
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
| | - David S. Fay
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
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35
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Sohn BH, Park IY, Lee JJ, Yang SJ, Jang YJ, Park KC, Kim DJ, Lee DC, Sohn HA, Kim TW, Yoo HS, Choi JY, Bae YS, Yeom YI. Functional switching of TGF-beta1 signaling in liver cancer via epigenetic modulation of a single CpG site in TTP promoter. Gastroenterology 2010; 138:1898-908. [PMID: 20038433 DOI: 10.1053/j.gastro.2009.12.044] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 11/16/2009] [Accepted: 12/17/2009] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS Acquisition of resistance to the antiproliferative effect of transforming growth factor (TGF)-beta1 is crucial for the malignant progression of cancers. In this study, we sought to determine whether deregulated expression of tristetrapolin (TTP), a negative posttranscriptional regulator of c-Myc, confers resistance to the antiproliferative effects of TGF-beta1 on liver cancer cells. METHODS The epigenetics of TTP promoter regulation and its effects on TGF-beta1 signaling were examined in hepatocellular carcinoma (HCC) cell lines and patient tissues. RESULTS TTP was down-regulated in HCC cell lines (10/11), compared with normal liver, as well as in tumor tissues (19/24) from paired HCC specimens. Methylation of a specific single CpG site located within the TGF-beta1-responsive region (TRR) of the TTP promoter was significantly associated with TTP down-regulation in both HCC cell lines and tumor tissues (r = -0.606383, P < .001). The singly methylated CpG site was specifically bound by a transcriptional repressor complex consisting of MECP2/c-Ski/DNMT3A and abolished the TGF-beta1-induced as well as basal-level expression of TTP. The epigenetic inactivation of TTP led to an increased half-life of c-Myc mRNA and blocked the cytostatic effect of TGF-beta1. Statistically significant correlations were observed between the single CpG site methylation and expression levels of TTP or c-Myc in clinical samples of HCC. CONCLUSIONS Abrogation of the post-transcriptional regulation of c-Myc via methylation of a specific single CpG site in the TTP promoter presents a novel mechanism for the gain of selective resistance to the antiproliferative signaling of TGF-beta1 in HCC.
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Affiliation(s)
- Bo Hwa Sohn
- Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
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36
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McIntyre NA, McInnes C, Griffiths G, Barnett AL, Kontopidis G, Slawin AMZ, Jackson W, Thomas M, Zheleva DI, Wang S, Blake DG, Westwood NJ, Fischer PM. Design, synthesis, and evaluation of 2-methyl- and 2-amino-N-aryl-4,5-dihydrothiazolo[4,5-h]quinazolin-8-amines as ring-constrained 2-anilino-4-(thiazol-5-yl)pyrimidine cyclin-dependent kinase inhibitors. J Med Chem 2010; 53:2136-45. [PMID: 20146435 DOI: 10.1021/jm901660c] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Following the recent discovery and development of 2-anilino-4-(thiazol-5-yl)pyrimidine cyclin dependent kinase (CDK) inhibitors, a program was initiated to evaluate related ring-constrained analogues, specifically, 2-methyl- and 2-amino-N-aryl-4,5-dihydrothiazolo[4,5-h]quinazolin-8-amines for inhibition of CDKs. Here we report the rational design, synthesis, structure-activity relationships (SARs), and cellular mode-of-action profile of these second generation CDK inhibitors. Many of the analogues from this chemical series inhibit CDKs with very low nanomolar K(i) values. The most potent compound reported in this study inhibits CDK2 with an IC(50) of 0.7 nM ([ATP] = 100 microM). Furthermore, an X-ray crystal structure of 2-methyl-N-(3-(nitro)phenyl)-4,5-dihydrothiazolo[4,5-h]quinazolin-8-amine (11g), a representative from the chemical series in complex with cyclin A-CDK2, is reported, confirming the design rationale and expected binding mode within the CDK2 ATP binding pocket.
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Affiliation(s)
- Neil A McIntyre
- School of Chemistry and Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
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37
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Hirai H, Takahashi-Suziki I, Shimomura T, Fukasawa K, Machida T, Takaki T, Kobayashi M, Eguchi T, Oki H, Arai T, Ichikawa K, Hasako S, Kodera T, Kawanishi N, Nakatsuru Y, Kotani H, Iwasawa Y. Potent anti-tumor activity of a macrocycle-quinoxalinone class pan-Cdk inhibitor in vitro and in vivo. Invest New Drugs 2010; 29:534-43. [PMID: 20084424 DOI: 10.1007/s10637-009-9384-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 12/22/2009] [Indexed: 11/24/2022]
Abstract
Deregulation of cell-cycle control is a hallmark of cancer. Thus, cyclin-dependent kinases (Cdks) are an attractive target for the development of anti-cancer drugs. Here, we report the biological characterization of a highly potent pan-Cdk inhibitor with a macrocycle-quinoxalinone structure. Compound M inhibited Cdk1, 2, 4, 5, 6, and 9 with equal potency in the nM range and was selective against kinases other than Cdks. This compound inhibited multiple events in the cell cycle in vitro, including retinoblastoma protein (pRb) phosphorylation, E2F-dependent transcription, DNA replication (determined by bromodeoxyuridine incorporation), and mitosis completion (assayed by flow cytometry) in the 10 nM range. Moreover, this compound induced cell death, as determined by induction of the subG1 fraction, activated caspase-3, and anexin V. In vivo, Compound M showed anti-tumor efficacy at a tolerated dose. In a nude rat xenograft tumor model, an 8-h constant infusion of Compound M inhibited pRb phosphorylation and induced apoptosis in tumor cells at ~ 30 nM, which led to the inhibition of tumor growth. Immunosuppression was the only liability observed at this dose, but immune function returned to normal after 10 days. Suppression of pRb phosphorylation in tumor cells was clearly correlated with tumor cell growth inhibition and cell death in vitro and in vivo. In vivo, Compound M inhibited pRb phosphorylation in both tumor and gut crypt cells. Rb phosphorylation may be a suitable pharmacodynamic biomarker in both tumors and normal tissues for monitoring target engagement and predicting the efficacy of Compound M.
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Affiliation(s)
- Hiroshi Hirai
- Department of Oncology, Banyu Tsukuba Research Institute, Merck Research Laboratories, Tsukuba, Ibaraki, 300-2611, Japan.
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38
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Singh N, Ma Z, Gemmill T, Wu X, Defiglio H, Rossettini A, Rabeler C, Beane O, Morse RH, Palumbo MJ, Hanes SD. The Ess1 prolyl isomerase is required for transcription termination of small noncoding RNAs via the Nrd1 pathway. Mol Cell 2009; 36:255-66. [PMID: 19854134 DOI: 10.1016/j.molcel.2009.08.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 07/03/2009] [Accepted: 08/13/2009] [Indexed: 12/17/2022]
Abstract
Genome-wide studies have identified abundant small, noncoding RNAs, including small nuclear RNAs, small nucleolar RNAs (snoRNAs), cryptic unstable transcripts (CUTs), and upstream regulatory RNAs (uRNAs), that are transcribed by RNA polymerase II (pol II) and terminated by an Nrd1-dependent pathway. Here, we show that the prolyl isomerase Ess1 is required for Nrd1-dependent termination of noncoding RNAs. Ess1 binds the carboxy-terminal domain (CTD) of pol II and is thought to regulate transcription by conformational isomerization of Ser-Pro bonds within the CTD. In ess1 mutants, expression of approximately 10% of the genome was altered, due primarily to defects in termination of snoRNAs, CUTs, stable unannotated transcripts, and uRNAs. Ess1 promoted dephosphorylation of Ser5 (but not Ser2) within the CTD, most likely by the Ssu72 phosphatase. We also provide evidence for a competition between Nrd1 and Pcf11 for CTD binding that is regulated by Ess1. These data indicate that a prolyl isomerase is required for specifying the "CTD code."
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Affiliation(s)
- Navjot Singh
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA
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39
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Luo L, Gassman KL, Petell LM, Wilson CL, Bewersdorf J, Shopland LS. The nuclear periphery of embryonic stem cells is a transcriptionally permissive and repressive compartment. J Cell Sci 2009; 122:3729-37. [PMID: 19773359 DOI: 10.1242/jcs.052555] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Chromatin adapts a distinct structure and epigenetic state in embryonic stem cells (ESCs), but how chromatin is three-dimensionally organized within the ESC nucleus is poorly understood. Because nuclear location can influence gene expression, we examined the nuclear distributions of chromatin with key epigenetic marks in ESC nuclei. We focused on chromatin at the nuclear periphery, a compartment that represses some but not all associated genes and accumulates facultative heterochromatin in differentiated cells. Using a quantitative, cytological approach, we measured the nuclear distributions of genes in undifferentiated mouse ESCs according to epigenetic state and transcriptional activity. We found that trimethyl histone H3 lysine 27 (H3K27-Me(3)), which marks repressed gene promoters, is enriched at the ESC nuclear periphery. In addition, this compartment contains 10-15% of chromatin with active epigenetic marks and hundreds of transcription sites. Surprisingly, comparisons with differentiated cell types revealed similar nuclear distributions of active chromatin. By contrast, H3K27-Me(3) was less concentrated at the nuclear peripheries of differentiated cells. These findings demonstrate that the nuclear periphery is an epigenetically dynamic compartment that might be distinctly marked in pluripotent ESCs. In addition, our data indicate that the nuclear peripheries of multiple cell types can contain a significant fraction of both active and repressed genes.
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Affiliation(s)
- Li Luo
- Institute for Molecular Biophysics, The Jackson Laboratory, Bar Harbor, ME 04609, USA
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40
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Abstract
The heat shock protein (HSP) molecular chaperones are the primary cellular defense against damage to the proteome, initiating refolding of denatured proteins and regulating degradation after severe protein damage. Many neurodegenerative disorders involve aberrant protein folding and protein damage, which accumulates in an age-dependent manner. Ageing is associated with the decrease in activity of the heat shock transcription factors (HSF) that regulate HSP gene transcription. Neuronal cells seem particularly vulnerable in this sense as HSF activity and HSP expression are relatively weak in such cells and motor neurons appear to require input of HSP secreted from adjacent glial cells to maintain adequate molecular chaperone levels. It may be significant that motor neurons have been shown to be the sensitive cells in the ageing of Drosophila and C. elegans and that these organisms may acquire extended lifespans with over-expression of small heat shock proteins and HSF1. HSF1 transcriptional activity has been discussed in neuronal cells, concentrating on the regulation and activity of HSF1 and HSF2 and their role in HSP expression, during neurodegenerative diseases and as mediators of cell survival.
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Affiliation(s)
- J Tonkiss
- Center for Behavioral Development, Boston University School of Medicine, Boston, MA, USA
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Functional interaction of the Ess1 prolyl isomerase with components of the RNA polymerase II initiation and termination machineries. Mol Cell Biol 2009; 29:2925-34. [PMID: 19332564 DOI: 10.1128/mcb.01655-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) is a reiterated heptad sequence (Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7) that plays a key role in the transcription cycle, coordinating the exchange of transcription and RNA processing factors. The structure of the CTD is flexible and undergoes conformational changes in response to serine phosphorylation and proline isomerization. Here we report that the Ess1 peptidyl prolyl isomerase functionally interacts with the transcription initiation factor TFIIB and with the Ssu72 CTD phosphatase and Pta1 components of the CPF 3'-end processing complex. The ess1(A144T) and ess1(H164R) mutants, initially described by Hanes and coworkers (Yeast 5:55-72, 1989), accumulate the pSer5 phosphorylated form of Pol II; confer phosphate, galactose, and inositol auxotrophies; and fail to activate PHO5, GAL10, and INO1 reporter genes. These mutants are also defective for transcription termination, but in vitro experiments indicate that this defect is not caused by altering the processing efficiency of the cleavage/polyadenylation machinery. Consistent with a role in initiation and termination, Ess1 associates with the promoter and terminator regions of the PMA1 and PHO5 genes. We propose that Ess1 facilitates pSer5-Pro6 dephosphorylation by generating the CTD structural conformation recognized by the Ssu72 phosphatase and that pSer5 dephosphorylation affects both early and late stages of the transcription cycle.
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Abstract
The cell cycle governs the transition from quiescence through cell growth to proliferation. The key parts of the cell cycle machinery are the cyclin-dependent kinases (CDKS) and the regulatory proteins called cyclins. The CDKS are rational targets for cancer therapy because their expression in cancer cells is often aberrant and their inhibition can induce cell death. Inhibitors of CDKS can also block transcription.Several drugs targeting the cell cycle have entered clinical trials. These agents include flavopiridol, indisulam, AZD5438, SNS-032, bryostatin-1, seliciclib, PD 0332991, and SCH 727965. Phase i studies have demonstrated that these drugs can generally be administered safely. Phase ii studies have shown little single-agent activity in solid tumors, but combination studies with cytotoxic chemotherapy have been more promising. In hematologic malignancies, reports have shown encouraging single-agent and combination activity. Pharmacodynamic studies show that the dose and schedule of these drugs are crucial to permit maximum therapeutic effect.
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Affiliation(s)
- M.A. Dickson
- Department of Medicine, Division of Solid Tumor Oncology, Melanoma and Sarcoma Service, and Laboratory of New Drug Development, Memorial Sloan–Kettering Cancer Center, New York, NY, U.S.A
| | - G.K. Schwartz
- Department of Medicine, Division of Solid Tumor Oncology, Melanoma and Sarcoma Service, and Laboratory of New Drug Development, Memorial Sloan–Kettering Cancer Center, New York, NY, U.S.A
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43
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Ahn SH, Keogh MC, Buratowski S. Ctk1 promotes dissociation of basal transcription factors from elongating RNA polymerase II. EMBO J 2009; 28:205-12. [PMID: 19131970 PMCID: PMC2632940 DOI: 10.1038/emboj.2008.280] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 12/04/2008] [Indexed: 02/02/2023] Open
Abstract
As RNA polymerase II (RNApII) transitions from initiation to elongation, Mediator and the basal transcription factors TFIID, TFIIA, TFIIH, and TFIIE remain at the promoter as part of a scaffold complex, whereas TFIIB and TFIIF dissociate. The yeast Ctk1 kinase associates with elongation complexes and phosphorylates serine 2 in the YSPTSPS repeats of the Rpb1 C-terminal domain, a modification that couples transcription to mRNA 3'-end processing. The higher eukaryotic kinase Cdk9 not only performs a similar function, but also functions at the 5'-end of genes in the transition from initiation to elongation. In strains lacking Ctk1, many basal transcription factors cross-link throughout transcribed regions, apparently remaining associated with RNApII until it terminates. Consistent with this observation, preinitiation complexes formed on immobilized templates with transcription extracts lacking Ctk1 leave lower levels of the scaffold complex behind after escape. Taken together, these results suggest that Ctk1 is necessary for the release of RNApII from basal transcription factors. Interestingly, this function of Ctk1 is independent of its kinase activity, suggesting a structural function of the protein.
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Affiliation(s)
- Seong Hoon Ahn
- Division of Molecular and Life Science, College of Science and Technology, Hanyang University, Ansan, Republic of Korea.
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44
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Functional Evolution of Cyclin-Dependent Kinases. Mol Biotechnol 2009; 42:14-29. [DOI: 10.1007/s12033-008-9126-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 11/01/2008] [Indexed: 10/21/2022]
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45
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Arabidopsis thaliana PRP40s are RNA polymerase II C-terminal domain-associating proteins. Arch Biochem Biophys 2009; 484:30-8. [PMID: 19467629 DOI: 10.1016/j.abb.2009.01.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 11/22/2022]
Abstract
The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II functions as a scaffold for RNA processing machineries that recognize differentially phosphorylated conserved (YSPTSPS)(n) repeats. Evidence indicates that proteins that regulate the phosphorylation status of the CTD are determinants of growth, development, and stress responses of plants; however, little is known about the mechanisms that translate the CTD phosphoarray into physiological outputs. We report the bioinformatic identification of a family of three phospho-CTD-associated proteins (PCAPs) in Arabidopsis and the characterization of the AtPRP40 (Arabidopsis thaliana PRE-mRNA-PROCESSING PROTEIN 40) family as PCAPs. AtPRP40s-CTD/CTD-PO(4) interactions were confirmed using the yeast two-hybrid assay and far-Western blotting. WW domains at the N-terminus of AtPRP40b mediate the AtPRP40b-CTD/CTD-PO(4) interaction. Although AtPRP40s interact with both phosphorylated and unphosphorylated CTD in vitro, there is a strong preference for the phosphorylated form in Arabidopsis cell extract. AtPRP40s are ubiquitously expressed and localize to the nucleus. These results establish that AtPRP40s are specific PCAPs, which is consistent with the predicted function of the AtPRP40 family in pre-mRNA splicing.
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46
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Lolli G. Binding to DNA of the RNA-polymerase II C-terminal domain allows discrimination between Cdk7 and Cdk9 phosphorylation. Nucleic Acids Res 2009; 37:1260-8. [PMID: 19136461 PMCID: PMC2651791 DOI: 10.1093/nar/gkn1061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The C-terminal domain (CTD) of RNA polymerase II regulates transcription through spatially and temporally coordinated events. Previous work had established that the CTD binds DNA but the significance of this interaction has not been determined. The present work shows that the CTD binds DNA in its unphosphorylated form, the form in which it is present in the pre-initiation complex. The CTD/DNA complex is recognized by and is phosphorylated by Cdk7 but not by Cdk9. Model-building studies indicate the structural mechanism underlying such specificity involves interaction of Cdk7 with DNA in the context of the CTD/DNA complex. The model has been tested by mutagenesis experiments. CTD dissociates from DNA following phosphorylation by Cdk7, allowing transcription initiation. The CTD then becomes accessible for further phosphorylation by Cdk9 that drives the transition to transcription elongation.
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Affiliation(s)
- Graziano Lolli
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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Bromodomain protein Brd4 regulates human immunodeficiency virus transcription through phosphorylation of CDK9 at threonine 29. J Virol 2008; 83:1036-44. [PMID: 18971272 DOI: 10.1128/jvi.01316-08] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Positive transcription elongation factor b (P-TEFb), composed of cyclin-dependent kinase 9 (CDK9) and cyclin T, is a global transcription factor for eukaryotic gene expression, as well as a key factor for human immunodeficiency virus (HIV) transcription elongation. P-TEFb phosphorylates the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II (RNAP II), facilitating the transition from nonprocessive to processive transcription elongation. Recently, the bromodomain protein Brd4 has been shown to interact with the low-molecular-weight, active P-TEFb complex and recruit P-TEFb to the HIV type 1 long terminal repeat (LTR) promoter. However, the subsequent events through which Brd4 regulates CDK9 kinase activity and RNAP II-dependent transcription are not clearly understood. Here we provide evidence that Brd4 regulates P-TEFb kinase activity by inducing a negative pathway. Moreover, by analyzing stepwise initiation and elongation complexes, we demonstrate that P-TEFb activity is regulated in the transcription complex. Brd4 induces phosphorylation of CDK9 at threonine 29 (T29) in the HIV transcription initiation complex, inhibiting CDK9 kinase activity. P-TEFb inhibition is transient, as Brd4 is released from the transcription complex between positions +14 and +36. Removal of the phosphate group at T29 by an incoming phosphatase released P-TEFb activity, resulting in increased RNAP II CTD phosphorylation and transcription. Finally, we present chromatin immunoprecipitation studies showing that CDK9 with phosphorylated T29 is associated with the HIV promoter region in the integrated and transcriptionally silent HIV genome.
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Wilkes JM, Doerig C. The protein-phosphatome of the human malaria parasite Plasmodium falciparum. BMC Genomics 2008; 9:412. [PMID: 18793411 PMCID: PMC2559854 DOI: 10.1186/1471-2164-9-412] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 09/15/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria, caused by the parasitic protist Plasmodium falciparum, represents a major public health problem in the developing world. The P. falciparum genome has been sequenced, which provides new opportunities for the identification of novel drug targets. We report an exhaustive analysis of the P. falciparum genomic database (PlasmoDB) aimed at identifying and classifying all protein phosphatases (PP) in this organism. RESULTS Using a variety of bioinformatics tools, we identified 27 malarial putative PP sequences within the four major established PP families, plus 7 sequences that we predict to dephosphorylate "non-protein" substrates. We constructed phylogenetic trees to position these sequences relative to PPs from other organisms representing all major eukaryotic phyla except Cercozoans (for which no full genome sequence is available). Predominant observations were: (i) P. falciparum possessed the smallest phosphatome of any of the organisms investigated in this study; (ii) no malarial PP clustered with the tyrosine-specific subfamily of the PTP group (iii) a cluster of 7 closely related members of the PPM/PP2C family is present, and (iv) some P. falciparum protein phosphatases are present in clades lacking any human homologue. CONCLUSION The considerable phylogenetic distance between Apicomplexa and other Eukaryotes is reflected by profound divergences between the phosphatome of malaria parasites and those of representative organisms from all major eukaryotic phyla, which might be exploited in the context of efforts for the discovery of novel targets for antimalarial chemotherapy.
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Affiliation(s)
- Jonathan M Wilkes
- INSERM U609, Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow, Scotland, UK.
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TFIID component TAF7 functionally interacts with both TFIIH and P-TEFb. Proc Natl Acad Sci U S A 2008; 105:5367-72. [PMID: 18391197 DOI: 10.1073/pnas.0801637105] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcription consists of a series of highly regulated steps: assembly of the preinitiation complex (PIC) at the promoter, initiation, elongation, and termination. PIC assembly is nucleated by TFIID, a complex composed of the TATA-binding protein (TBP) and a series of TBP-associated factors (TAFs). One component, TAF7, is incorporated in the PIC through its interaction with TFIID but is released from TFIID upon transcription initiation. We now report that TAF7 interacts with the transcription factors, TFIIH and P-TEFb, resulting in the inhibition of their Pol II CTD kinase activities. Importantly, in in vitro transcription reactions, TAF7 inhibits steps after PIC assembly and formation of the first phosphodiester bonds. Further, in vivo TAF7 coelongates with P-TEFb and Pol II downstream of the promoter. We propose a model in which TAF7 contributes to the regulation of the transition from PIC assembly to initiation and elongation.
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p53 and TFIIEalpha share a common binding site on the Tfb1/p62 subunit of TFIIH. Proc Natl Acad Sci U S A 2007; 105:106-11. [PMID: 18160537 DOI: 10.1073/pnas.0707892105] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The general transcription factor IIH is recruited to the transcription preinitiation complex through an interaction between its p62/Tfb1 subunit and the alpha-subunit of the general transcription factor IIE (TFIIEalpha). We have determined that the acidic carboxyl terminus of TFIIEalpha (TFIIEalpha(336-439)) directly binds the amino-terminal PH domain of p62/Tfb1 with nanomolar affinity. NMR mapping and mutagenesis studies demonstrate that the TFIIEalpha binding site on p62/Tfb1 is identical to the binding site for the second transactivation domain of p53 (p53 TAD2). In addition, we demonstrate that TFIIEalpha(336-439) is capable of competing with p53 for a common binding site on p62/Tfb1 and that TFIIEalpha(336-439) and the diphosphorylated form (pS46/pT55) of p53 TAD2 have similar binding constants. NMR structural studies reveal that TFIIEalpha(336-439) contains a small domain (residues 395-433) folded in a novel betabetaalphaalphaalpha topology. NMR mapping studies demonstrate that two unstructured regions (residues 377-393 and residues 433-439) located on either side of the folded domain appear to be required for TFIIEalpha(336-439) binding to p62/Tfb1 and that these two unstructured regions are held close to each other in three-dimensional space by the novel structured domain. We also demonstrate that, like p53, TFIIEalpha(336-439) can activate transcription in vivo. These results point to an important interplay between the general transcription factor TFIIEalpha and the tumor suppressor protein p53 in regulating transcriptional activation that may be modulated by the phosphorylation status of p53.
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