Transcription without XPB Establishes a Unified Helicase-Independent Mechanism of Promoter Opening in Eukaryotic Gene Expression.
Transcription starts with the assembly of pre-initiation complexes on promoters followed by their opening. Current models suggest that class II gene transcription requires ATP and the TFIIH XPB subunit to open a promoter. Here, we observe that XPB depletion surprisingly leaves transcription virtually intact. In contrast, inhibition of XPB ATPase activity affects transcription, revealing that mRNA expression paradoxically accommodates the absence of XPB while being sensitive to the inhibition of its ATPase activity. The XPB-depleted TFIIH complex is recruited to active promoters and contributes to transcription. We finally demonstrate that the XPB ATPase activity is only used to relieve a transcription initiation block imposed by XPB itself. In the absence of this block, transcription initiation can take place without XPB ATPase activity. These results suggest that a helicase is dispensable for mRNA transcription, thereby unifying the mechanism of promoter DNA opening for the three eukaryotic RNA polymerases.
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Sergey
S
Alekseev
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Zita
Z
Nagy
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Jérémy
J
Sandoz
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Amélie
A
Weiss
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Jean-Marc
JM
Egly
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France.
Nicolas
N
Le May
IGBMC, Department of Functional Genomics and Cancer, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67404 Illkirch, France. Electronic address: fredr@igbmc.fr.
Frederic
F
Coin
D000251:Adenosine Triphosphatases / Q000378:metabolism; D002460:Cell Line; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D009154:Mutation; D011401:Promoter Regions, Genetic; D017423:Sequence Analysis, RNA / Q000379:methods; D051758:Transcription Factor TFIIH / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; C072022:XPBC-ERCC-3 protein; D051758:Transcription Factor TFIIH; D000251:Adenosine Triphosphatases; D004265:DNA Helicases