title: Defective transcription/repair factor IIH recruitment to specific UV lesions in trichothiodystrophy syndrome.
abstract: Most trichothiodystrophy (TTD) patients present mutations in the xeroderma pigmentosum D (XPD) gene, coding for a subunit of the transcription/repair factor IIH (TFIIH) complex involved in nucleotide excision repair (NER) and transcription. After UV irradiation, most TTD/XPD patients are more severely affected in the NER of cyclobutane pyrimidine dimers (CPD) than of 6-4-photoproducts (6-4PP). The reasons for this differential DNA repair defect are unknown. Here we report the first study of NER in response to CPDs or 6-4PPs separately analyzed in primary fibroblasts. This was done by using heterologous photorepair; recombinant adenovirus vectors carrying photolyases enzymes that repair CPD or 6-4PP specifically by using the energy of light were introduced in different cell lines. The data presented here reveal that some TTD/XPD mutations affect the recruitment of TFIIH specifically to CPDs, but not to 6-4PPs. This deficiency is further confirmed by the inability of TTD/XPD cells to recruit, specifically for CPDs, NER factors that arrive in a TFIIH-dependent manner later in the NER pathway. For 6-4PPs, we show that TFIIH complexes carrying an NH(2)-terminal XPD mutated protein are also deficient in recruitment of NER proteins downstream of TFIIH. Treatment with the histone deacetylase inhibitor trichostatin A allows the recovery of TFIIH recruitment to CPDs in the studied TTD cells and, for COOH-terminal XPD mutations, increases the repair synthesis and survival after UV, suggesting that this defect can be partially related with accessibility of DNA damage in closed chromatin regions.
authors.affiliation: Laboratory of Genetic Stability and Oncogenesis, Centre National de la Recherche Scientifique, Formation de Recherche en Evolution 2939, Institut Gustave Roussy, Université Paris-Sud, Villejuif, France. vchigancas@gmail.com
authors.forename: Vanessa
authors.initials: V
authors.lastname: Chiganças
authors.forename: Keronninn M
authors.initials: KM
authors.lastname: Lima-Bessa
authors.forename: Anne
authors.initials: A
authors.lastname: Stary
authors.forename: Carlos F M
authors.initials: CF
authors.lastname: Menck
authors.forename: Alain
authors.initials: A
authors.lastname: Sarasin
mesh_terms: D002460:Cell Line; D004260:DNA Repair; D005455:Fluorescent Antibody Technique; D006801:Humans; D011740:Pyrimidine Dimers; D051758:Transcription Factor TFIIH / Q000235:genetics / Q000378:metabolism*; D054463:Trichothiodystrophy Syndromes / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; C058406:pyrimidine-pyrimidone dimer; D051758:Transcription Factor TFIIH