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Rallabandi HR, Choi H, Cha H, Kim YJ. Research Trends in C-Terminal Domain Nuclear Envelope Phosphatase 1. Life (Basel) 2023; 13:1338. [PMID: 37374122 DOI: 10.3390/life13061338] [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: 04/11/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1, formerly Dullard) is a member of the newly emerging protein phosphatases and has been recognized in neuronal cell tissues in amphibians. It contains the phosphatase domain in the C-terminal, and the sequences are conserved in various taxa of organisms. CTDNEP1 has several roles in novel biological activities such as neural tube development in embryos, nuclear membrane biogenesis, regulation of bone morphogenetic protein signaling, and suppression of aggressive medulloblastoma. The three-dimensional structure of CTDNEP1 and the detailed action mechanisms of CTDNEP1's functions have yet to be determined for several reasons. Therefore, CTDNEP1 is a protein phosphatase of interest due to recent exciting and essential works. In this short review, we summarize the presented biological roles, possible substrates, interacting proteins, and research prospects of CTDNEP1.
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Affiliation(s)
- Harikrishna Reddy Rallabandi
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Haewon Choi
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Hyunseung Cha
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Young Jun Kim
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
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2
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Escobedo A, Piccirillo J, Aranda J, Diercks T, Mateos B, Garcia-Cabau C, Sánchez-Navarro M, Topal B, Biesaga M, Staby L, Kragelund BB, García J, Millet O, Orozco M, Coles M, Crehuet R, Salvatella X. A glutamine-based single α-helix scaffold to target globular proteins. Nat Commun 2022; 13:7073. [PMID: 36400768 PMCID: PMC9674830 DOI: 10.1038/s41467-022-34793-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022] Open
Abstract
The binding of intrinsically disordered proteins to globular ones can require the folding of motifs into α-helices. These interactions offer opportunities for therapeutic intervention but their modulation with small molecules is challenging because they bury large surfaces. Linear peptides that display the residues that are key for binding can be targeted to globular proteins when they form stable helices, which in most cases requires their chemical modification. Here we present rules to design peptides that fold into single α-helices by instead concatenating glutamine side chain to main chain hydrogen bonds recently discovered in polyglutamine helices. The resulting peptides are uncharged, contain only natural amino acids, and their sequences can be optimized to interact with specific targets. Our results provide design rules to obtain single α-helices for a wide range of applications in protein engineering and drug design.
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Affiliation(s)
- Albert Escobedo
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain.
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Jonathan Piccirillo
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Juan Aranda
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Tammo Diercks
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160, Derio, Spain
| | - Borja Mateos
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Carla Garcia-Cabau
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Macarena Sánchez-Navarro
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina López Neyra (IPBLN-CSIC), Armilla, Granada, Spain
| | - Busra Topal
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Mateusz Biesaga
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Lasse Staby
- REPIN and Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Birthe B Kragelund
- REPIN and Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Jesús García
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Oscar Millet
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160, Derio, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain
- Department of Biochemistry and Biomedicine, University of Barcelona, Avinguda Diagonal 645, 08028, Barcelona, Spain
| | - Murray Coles
- Department of Protein Evolution, Max Planck Institute for Biology, Max-Planck-Ring 5, 72076, Tubingen, Germany
| | - Ramon Crehuet
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain
| | - Xavier Salvatella
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028, Barcelona, Spain.
- ICREA, Passeig Lluís Companys 23, 08010, Barcelona, Spain.
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3
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Regulation of Androgen Receptor Activity by Transient Interactions of Its Transactivation Domain with General Transcription Regulators. Structure 2017; 26:145-152.e3. [PMID: 29225078 DOI: 10.1016/j.str.2017.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/12/2017] [Accepted: 11/10/2017] [Indexed: 11/23/2022]
Abstract
The androgen receptor is a transcription factor that plays a key role in the development of prostate cancer, and its interactions with general transcription regulators are therefore of potential therapeutic interest. The mechanistic basis of these interactions is poorly understood due to the intrinsically disordered nature of the transactivation domain of the androgen receptor and the generally transient nature of the protein-protein interactions that trigger transcription. Here, we identify a motif of the transactivation domain that contributes to transcriptional activity by recruiting the C-terminal domain of subunit 1 of the general transcription regulator TFIIF. These findings provide molecular insights into the regulation of androgen receptor function and suggest strategies for treating castration-resistant prostate cancer.
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4
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Mayfield JE, Burkholder NT, Zhang YJ. Dephosphorylating eukaryotic RNA polymerase II. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:372-87. [PMID: 26779935 DOI: 10.1016/j.bbapap.2016.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 12/20/2022]
Abstract
The phosphorylation state of the C-terminal domain of RNA polymerase II is required for the temporal and spatial recruitment of various factors that mediate transcription and RNA processing throughout the transcriptional cycle. Therefore, changes in CTD phosphorylation by site-specific kinases/phosphatases are critical for the accurate transmission of information during transcription. Unlike kinases, CTD phosphatases have been traditionally neglected as they are thought to act as passive negative regulators that remove all phosphate marks at the conclusion of transcription. This over-simplified view has been disputed in recent years and new data assert the active and regulatory role phosphatases play in transcription. We now know that CTD phosphatases ensure the proper transition between different stages of transcription, balance the distribution of phosphorylation for accurate termination and re-initiation, and prevent inappropriate expression of certain genes. In this review, we focus on the specific roles of CTD phosphatases in regulating transcription. In particular, we emphasize how specificity and timing of dephosphorylation are achieved for these phosphatases and consider the various regulatory factors that affect these dynamics.
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Affiliation(s)
- Joshua E Mayfield
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Nathaniel T Burkholder
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Yan Jessie Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
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5
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Schwer B, Ghosh A, Sanchez AM, Lima CD, Shuman S. Genetic and structural analysis of the essential fission yeast RNA polymerase II CTD phosphatase Fcp1. RNA (NEW YORK, N.Y.) 2015; 21:1135-1146. [PMID: 25883047 PMCID: PMC4436666 DOI: 10.1261/rna.050286.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 02/25/2015] [Indexed: 06/04/2023]
Abstract
Protein phosphatases regulate mRNA synthesis and processing by remodeling the carboxy-terminal domain (CTD) of RNA polymerase II (Pol2) to dynamically inscribe a Pol2 CTD code. Fission yeast Fcp1 (SpFcp1) is an essential 723-amino acid CTD phosphatase that preferentially hydrolyzes Ser2-PO4 of the YS(2)PTSPS repeat. The SpFcp1 catalytic domain (aa 140-580) is composed of a DxDxT acyl-phosphatase module (FCPH) and a BRCT module. Here we conducted a genetic analysis of SpFcp1, which shows that (i) phosphatase catalytic activity is required for vegetative growth of fission yeast; (ii) the flanking amino-terminal domain (aa 1-139) and its putative metal-binding motif C(99)H(101)Cys(109)C(112) are essential; (iii) the carboxy-terminal domain (aa 581-723) is dispensable; (iv) a structurally disordered internal segment of the FCPH domain (aa 330-393) is dispensable; (v) lethal SpFcp1 mutations R271A and R299A are rescued by shortening the Pol2 CTD repeat array; and (vi) CTD Ser2-PO4 is not the only essential target of SpFcp1 in vivo. Recent studies highlight a second CTD code involving threonine phosphorylation of a repeat motif in transcription elongation factor Spt5. We find that Fcp1 can dephosphorylate Thr1-PO4 of the fission yeast Spt5 CTD nonamer repeat T(1)PAWNSGSK. We identify Arg271 as a governor of Pol2 versus Spt5 CTD substrate preference. Our findings implicate Fcp1 as a versatile sculptor of both the Pol2 and Spt5 CTD codes. Finally, we report a new 1.45 Å crystal structure of SpFcp1 with Mg(2+) and AlF3 that mimics an associative phosphorane transition state of the enzyme-aspartyl-phosphate hydrolysis reaction.
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Affiliation(s)
- Beate Schwer
- Microbiology and Immunology Department, Weill Cornell Medical College, New York, New York 10065, USA
| | - Agnidipta Ghosh
- Structural Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Ana M Sanchez
- Microbiology and Immunology Department, Weill Cornell Medical College, New York, New York 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA Howard Hughes Medical Institute, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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6
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Abstract
Transcription of eukaryotic protein-coding genes commences with the assembly of a conserved initiation complex, which consists of RNA polymerase II (Pol II) and the general transcription factors, at promoter DNA. After two decades of research, the structural basis of transcription initiation is emerging. Crystal structures of many components of the initiation complex have been resolved, and structural information on Pol II complexes with general transcription factors has recently been obtained. Although mechanistic details await elucidation, available data outline how Pol II cooperates with the general transcription factors to bind to and open promoter DNA, and how Pol II directs RNA synthesis and escapes from the promoter.
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7
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Kumar S, Showalter SA, Noid WG. Native-based simulations of the binding interaction between RAP74 and the disordered FCP1 peptide. J Phys Chem B 2013; 117:3074-85. [PMID: 23387368 DOI: 10.1021/jp310293b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
By dephosphorylating the C-terminal domain (CTD) of RNA polymerase II (Pol II), the Transcription Factor IIF (TFIIF)-associating CTD phosphatase (FCP1) performs an essential function in recycling Pol II for subsequent rounds of transcription. The interaction between FCP1 and TFIIF is mediated by the disordered C-terminal tail of FCP1, which folds to form an α-helix upon binding the RAP74 subunit of TFIIF. The present work reports a structure-based simulation study of this interaction between the folded winged-helix domain of RAP74 and the disordered C-terminal tail of FCP1. The comparison of measured and simulated chemical shifts suggests that the FCP1 peptide samples 40-60% of its native helical structure in the unbound disordered ensemble. Free energy calculations suggest that productive binding begins when RAP74 makes hydrophobic contacts with the C-terminal region of the FCP1 peptide. The FCP1 peptide then folds into an amphipathic helix by zipping up the binding interface. The relative plasticity of FCP1 results in a more cooperative binding mechanism, allows for a greater diversity of pathways leading to the bound complex, and may also eliminate the need for "backtracking" from contacts that form out of sequence.
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Affiliation(s)
- Sushant Kumar
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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8
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Lawrence CW, Showalter SA. Carbon-Detected (15)N NMR Spin Relaxation of an Intrinsically Disordered Protein: FCP1 Dynamics Unbound and in Complex with RAP74. J Phys Chem Lett 2012; 3:1409-1413. [PMID: 26286791 DOI: 10.1021/jz300432e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Intrinsically disordered proteins (IDPs) lack unique 3D structures under native conditions and as such exist as highly dynamic ensembles in solution. We present two (13)C-direct detection experiments for the measurement of (15)N NMR spin relaxation called the CON(T1)-IPAP and CON(T2)-IPAP that quantify backbone dynamics on a per-residue basis for IDPs in solution. These experiments have been applied to the intrinsically disordered C-terminal of FCP1, both free in solution and while bound to the RAP74 winged-helix domain. The results provide evidence that most of FCP1 remains highly dynamic in both states, while the 20 residues forming direct contact with RAP74 become more ordered in the complex. Parallel analysis of RAP74 backbone (15)N NMR spin relaxation reveals only very limited ordering of RAP74 upon FCP1 binding. Taken together, these data show that folding-upon-binding is highly local in this system, with disorder prevailing even in the complex.
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Affiliation(s)
- Chad W Lawrence
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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9
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Kilpatrick AM, Koharudin LMI, Calero GA, Gronenborn AM. Structural and binding studies of the C-terminal domains of yeast TFIIF subunits Tfg1 and Tfg2. Proteins 2011; 80:519-29. [PMID: 22095626 DOI: 10.1002/prot.23217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/12/2011] [Accepted: 09/27/2011] [Indexed: 12/13/2022]
Abstract
The general transcription factor TFIIF plays essential roles at several steps during eukaryotic transcription. While several studies have offered insights into the structure/function relationship in human TFIIF, much less is known about the yeast system. Here, we describe the first NMR structural and binding studies of the C-terminal domains (CTDs) of Tfg1 and Tfg2 subunits of Saccharomyces cerevisiae TFIIF. We used the program CS-ROSETTA to determine the three-dimensional folds of these domains in solution, and performed binding studies with DNA and protein targets. CS-ROSETTA models indicate that the Tfg1 and Tfg2 C-terminal domains have winged-helix architectures, similar to the human homologs. We showed that both Tfg1 and Tfg2 CTDs interact with double-stranded DNA oligonucleotides, and mapped the DNA binding interfaces using solution NMR. Tfg1-CTD, but not Tfg2-CTD, also binds to yeast FCP1, an RNA polymerase II-specific phosphatase, and we delineated the interaction surface with the CTD of FCP1. Our results provide insights into the structural basis of yeast TFIIF function and the differential roles of Tfg1 and Tfg2 subunits during transcription.
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Affiliation(s)
- Adina M Kilpatrick
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
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10
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Wostenberg C, Kumar S, Noid WG, Showalter SA. Atomistic Simulations Reveal Structural Disorder in the RAP74-FCP1 Complex. J Phys Chem B 2011; 115:13731-9. [DOI: 10.1021/jp208008m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Christopher Wostenberg
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Sushant Kumar
- Huck Insitutes for the Life Sciences, The Pennsylvania State University, Pennsylvania 16802, United States
| | - William G. Noid
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Scott A. Showalter
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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Falconer RJ, Collins BM. Survey of the year 2009: applications of isothermal titration calorimetry. J Mol Recognit 2010; 24:1-16. [DOI: 10.1002/jmr.1073] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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Jerebtsova M, Klotchenko SA, Artamonova TO, Ammosova T, Washington K, Egorov VV, Shaldzhyan AA, Sergeeva MV, Zatulovskiy EA, Temkina OA, Petukhov MG, Vasin AV, Khodorkovskii MA, Orlov YN, Nekhai S. Mass spectrometry and biochemical analysis of RNA polymerase II: targeting by protein phosphatase-1. Mol Cell Biochem 2010; 347:79-87. [PMID: 20941529 DOI: 10.1007/s11010-010-0614-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 09/28/2010] [Indexed: 01/21/2023]
Abstract
Transcription of eukaryotic genes is regulated by phosphorylation of serine residues of heptapeptide repeats of the carboxy-terminal domain (CTD) of RNA polymerase II (RNAPII). We previously reported that protein phosphatase-1 (PP1) dephosphorylates RNAPII CTD in vitro and inhibition of nuclear PP1-blocked viral transcription. In this article, we analyzed the targeting of RNAPII by PP1 using biochemical and mass spectrometry analysis of RNAPII-associated regulatory subunits of PP1. Immunoblotting showed that PP1 co-elutes with RNAPII. Mass spectrometry approach showed the presence of U2 snRNP. Co-immunoprecipitation analysis points to NIPP1 and PNUTS as candidate regulatory subunits. Because NIPP1 was previously shown to target PP1 to U2 snRNP, we analyzed the effect of NIPP1 on RNAPII phosphorylation in cultured cells. Expression of mutant NIPP1 promoted RNAPII phosphorylation suggesting that the deregulation of cellular NIPP1/PP1 holoenzyme affects RNAPII phosphorylation and pointing to NIPP1 as a potential regulatory factor in RNAPII-mediated transcription.
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Affiliation(s)
- Marina Jerebtsova
- Center for Molecular Physiology, Children's National Medical Center, Washington, DC, USA
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The RNA Pol II CTD phosphatase Fcp1 is essential for normal development in Drosophila melanogaster. Gene 2009; 446:58-67. [PMID: 19632310 DOI: 10.1016/j.gene.2009.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 07/09/2009] [Accepted: 07/17/2009] [Indexed: 11/23/2022]
Abstract
The reversible phosphorylation-dephosphorylation of RNA polymerase II (Pol II) large subunit carboxyl terminal domain (CTD) during transcription cycles in eukaryotic cells generates signals for the steps of RNA synthesis and maturation. The major phosphatase specific for CTD dephosphorylation from yeast to mammals is the TFIIF-interacting CTD-phosphatase, Fcp1. We report here on the in vivo analysis of Fcp1 function in Drosophila using transgenic lines in which the phosphatase production is misregulated. Fcp1 function is essential throughout Drosophila development and ectopic up- or downregulation of fcp1 results in lethality. The fly Fcp1 binds to specific regions of the polytene chromosomes at many sites colocalized with Pol II. In accord with the strong evolutional conservation of Fcp1: (1) the Xenopus fcp1 can substitute the fly fcp1 function, (2) similarly to its S. pombe homologue, Drosophila melanogaster (Dm)Fcp1 interacts with the RPB4 subunit of Pol II, and (3) transient expression of DmFcp1 has a negative effect on transcription in mammalian cells. The in vivo experimental system described here suggests that fly Fcp1 is associated with the transcription engaged Pol II and offers versatile possibilities for studying this evolutionary conserved essential enzyme.
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