The XPB subunit of repair/transcription factor TFIIH directly interacts with SUG1, a subunit of the 26S proteasome and putative transcription factor.
Mutations in the basal transcription initiation/DNA repair factor TFIIH are responsible for three human disorders: xeroderma pigmentosum (XP), cockayne syndrome (CS) and trichothiodystrophy (TTD). The non-repair features of CS and TTD are thought to be due to a partial inactivation of the transcription function of the complex. To search for proteins whose interaction with TFIIH subunits is disturbed by mutations in patients we used the yeast two-hybrid system and report the isolation of a novel XPB interacting protein, SUG1. The interaction was validated in vivo and in vitro in the following manner. (i) SUG1 interacts with XPB but not with the other core TFIIH subunits in the two-hybrid assay. (ii) Physical interaction is observed in a baculovirus co-expression system. (iii) In fibroblasts under non-overexpression conditions a portion of SUG1 is bound to the TFIIH holocomplex as deduced from co-purification, immunopurification and nickel-chelate affinity chromatography using functional tagged TFIIH. Furthermore, overexpression of SUG1 in normal fibroblasts induced arrest of transcription and a chromatin collapse in vivo. Interestingly, the interaction was diminished with a mutant form of XPB, thus providing a potential link with the clinical features of XP-B patients. Since SUG1 is an integral component of the 26S proteasome and may be part of the mediator, our findings disclose a SUG1-dependent link between TFIIH and the cellular machinery involved in protein modelling/degradation.
|Keywords||*Saccharomyces cerevisiae Proteins, *Transcription Factors, TFII, 0 (Carrier Proteins), 0 (DNA-Binding Proteins), 0 (Fungal Proteins), 0 (Oligodeoxyribonucleotides), 0 (RPT6 protein, S cerevisiae), 0 (Recombinant Proteins), 0 (Repressor Proteins), 0 (SUG1 protein, mammalian), 0 (Saccharomyces cerevisiae Proteins), 0 (Taf6 protein, Drosophila), 0 (Transcription Factors), 0 (Transcription Factors, TFII), 0 (thyroid-hormone-receptor interacting protein), 146045-44-5 (XPBC-ERCC-3 protein), 148710-81-0 (transcription factor TFIIH), Amino Acid Sequence, Animals, Base Sequence, Carrier Proteins/chemistry/*metabolism, Cell Line, Chromatography, Affinity, DNA Repair, DNA-Binding Proteins/*metabolism, EC 3.4 (Peptide Hydrolases), EC 3.4.99.- (ATP dependent 26S protease), Embryo, Fibroblasts, Fungal Proteins/chemistry/*metabolism, Gene Library, Hela Cells, Human, Mice, Mice, Inbred Strains, Molecular Sequence Data, Mutagenesis, Site-Directed, Oligodeoxyribonucleotides, Peptide Hydrolases/chemistry/*metabolism, Recombinant Proteins/isolation & purification/metabolism, Repressor Proteins/chemistry/*metabolism, Saccharomyces cerevisiae/genetics/metabolism, Sequence Alignment, Sequence Homology, Amino Acid, Sequence Tagged Sites, Spodoptera, Support, Non-U.S. Gov't, Trans-Activation (Genetics), Transcription Factors/isolation & purification/*metabolism, Transcription, Genetic, Transfection|
|Persistent URL||dx.doi.org/10.1093/nar/25.12.2274, hdl.handle.net/1765/3115|
Weeda, G., Rossignol, M., Fraser, R.A., Winkler, G.S., Vermeulen, W., van 't Veer, L.J., … Egly, J-M.. (1997). The XPB subunit of repair/transcription factor TFIIH directly interacts with SUG1, a subunit of the 26S proteasome and putative transcription factor.. Nucleic Acids Research, 25(12), 2274–2283. doi:10.1093/nar/25.12.2274