A new, tenth subunit of TFIIH is responsible for the DNA repair syndrome trichothiodystrophy group A.
DNA repair-deficient trichothiodystrophy (TTD) results from mutations in the XPD and XPB subunits of the DNA repair and transcription factor TFIIH. In a third form of DNA repair-deficient TTD, called group A, none of the nine subunits encoding TFIIH carried mutations; instead, the steady-state level of the entire complex was severely reduced. A new, tenth TFIIH subunit (TFB5) was recently identified in yeast. Here, we describe the identification of the human TFB5 ortholog and its association with human TFIIH. Microinjection of cDNA encoding TFB5 (GTF2H5, also called TTDA) corrected the DNA-repair defect of TTD-A cells, and we identified three functional inactivating mutations in this gene in three unrelated families with TTD-A. The GTF2H5 gene product has a role in regulating the level of TFIIH. The identification of a new evolutionarily conserved subunit of TFIIH implicated in TTD-A provides insight into TFIIH function in transcription, DNA repair and human disease.
Giglia-Mari
Giuseppina
G
Department of Genetics, Medical Genetic Cluster, Erasmus MC, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
Coin
Frederic
F
Ranish
Jeffrey A
JA
Hoogstraten
Deborah
D
Theil
Arjan
A
Wijgers
Nils
N
Jaspers
Nicolaas G J
NG
Raams
Anja
A
Argentini
Manuela
M
van der Spek
P J
PJ
Botta
Elena
E
Stefanini
Miria
M
Egly
Jean-Marc
JM
Aebersold
Ruedi
R
Hoeijmakers
Jan H J
JH
Vermeulen
Wim
W
D004260:DNA Repair; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008845:Microinjections; D016366:Open Reading Frames; D051758:Transcription Factor TFIIH; D019473:Transcription Factors, TFII / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
D019473:Transcription Factors, TFII; D051758:Transcription Factor TFIIH