TY - JOUR
T1 - Affinity purification of human DNA repair/transcription factor TFIIH using epitope-tagged xeroderma pigmentosum B protein
AU - Winkler, G. Sebastiaan
AU - Vermeulen, Wim
AU - Coin, Frédéric
AU - Egly, Jean Marc
AU - Hoeijmakers, Jan H.J.
AU - Weeda, Geert
PY - 1998/1/9
Y1 - 1998/1/9
N2 - TFIIH is a high molecular weight complex with a remarkable dual function in nucleotide excision repair and initiation of RNA polymerase II transcription. Mutations in the largest subunits, the XPB and XPD helicases, are associated with three inherited disorders: xeroderma pigmentosum, Cockayne's syndrome, and trichothiodystrophy. To facilitate the purification and biochemical characterization of this intricate complex, we generated a cell line stably expressing tagged XPB, allowing the immunopurification of the XPB protein and associated factors. Addition of two tags, a N-terminal hexameric histidine stretch and a C-terminal hemagglutinin epitope, to this highly conserved protein did not interfere with its functioning in repair and transcription. The hemagglutinin epitope allowed efficient TFIIH immunopurification to homogeneity from a fractionated whole cell extract in essentially one step. We conclude that the predominant active form of TFIIH is composed of nine subunits and that there is one molecule of XPB per TFIIH complex. The affinity-purified complex exhibits all expected TFIIH activities: DNA-dependent ATPase, helicase, C-terminal domain kinase, and participation in in vitro and in vivo nucleotide excision repair and in vitro transcription. The affinity purification procedure described here is fast and simple, does not require extensive chromatographic procedures, and yields highly purified, active TFIIH.
AB - TFIIH is a high molecular weight complex with a remarkable dual function in nucleotide excision repair and initiation of RNA polymerase II transcription. Mutations in the largest subunits, the XPB and XPD helicases, are associated with three inherited disorders: xeroderma pigmentosum, Cockayne's syndrome, and trichothiodystrophy. To facilitate the purification and biochemical characterization of this intricate complex, we generated a cell line stably expressing tagged XPB, allowing the immunopurification of the XPB protein and associated factors. Addition of two tags, a N-terminal hexameric histidine stretch and a C-terminal hemagglutinin epitope, to this highly conserved protein did not interfere with its functioning in repair and transcription. The hemagglutinin epitope allowed efficient TFIIH immunopurification to homogeneity from a fractionated whole cell extract in essentially one step. We conclude that the predominant active form of TFIIH is composed of nine subunits and that there is one molecule of XPB per TFIIH complex. The affinity-purified complex exhibits all expected TFIIH activities: DNA-dependent ATPase, helicase, C-terminal domain kinase, and participation in in vitro and in vivo nucleotide excision repair and in vitro transcription. The affinity purification procedure described here is fast and simple, does not require extensive chromatographic procedures, and yields highly purified, active TFIIH.
UR - http://www.scopus.com/inward/record.url?scp=0031975207&partnerID=8YFLogxK
U2 - 10.1074/jbc.273.2.1092
DO - 10.1074/jbc.273.2.1092
M3 - Article
C2 - 9422774
AN - SCOPUS:0031975207
SN - 0021-9258
VL - 273
SP - 1092
EP - 1098
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 2
ER -