The cdk7-cyclin H-MAT1 complex associated with TFIIH is localized in coiled bodies.
TFIIH is a general transcription factor for RNA polymerase II that in addition is involved in DNA excision repair. TFIIH is composed of eight or nine subunits and we show that at least four of them, namely cdk7, cyclin H, MAT1, and p62 are localized in the coiled body, a distinct subnuclear structure that is transcription dependent and highly enriched in small nuclear ribonucleoproteins. Although coiled bodies do not correspond to sites of transcription, in vivo incorporation of bromo-UTP shows that they are surrounded by transcription foci. Immunofluorescence analysis using antibodies directed against the essential repair factors proliferating cell nuclear antigen and XPG did not reveal labeling of the coiled body in either untreated cells or cells irradiated with UV light, arguing that coiled bodies are probably not involved in DNA repair mechanisms. The localization of cyclin H in the coiled body was predominantly detected during the G1 and S-phases of the cell cycle, whereas in G2 coiled bodies were very small or not detected. Finally, both cyclin H and cdk7 did not colocalize with P80 coilin after disruption of the coiled body, indicating that these proteins are specifically targeted to the small nuclear ribonucleoprotein-containing domain.
Jordan
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Institute of Histology and Embryology, Faculty of Medicine, University of Lisbon, Portugal.
Cunha
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Carmo-Fonseca
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D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002466:Cell Nucleolus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D056748:Cyclin H; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004260:DNA Repair; D016193:G1 Phase; D006367:HeLa Cells; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000378:metabolism*; D016196:S Phase; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic; D000095043:Cyclin-Dependent Kinase-Activating Kinase
C534751:CCNH protein, human; D002352:Carrier Proteins; D056748:Cyclin H; D016213:Cyclins; D003598:Cytoskeletal Proteins; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C104815:mitotic apparatus-associated protein p62, sea urchin; D051758:Transcription Factor TFIIH; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase; C000722416:CDK7 protein, human