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Updated: Oct 20, 2026

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Reconstitution of the transcription factor TFIIH: assignment of functions for the three enzymatic subunits, XPB, XPD,
1Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, C. U. de Strasbourg, France.
Abstract:
To understand the initiation of the transcription of protein-coding genes, we have dissected the role of the basal transcription/DNA repair factor TFIIH. Having succeeded in reconstituting a functionally active TFIIH from baculovirus recombinant polypeptides, we were able to analyze the role of XPB, XPD, and cdk7 subunits in the transcription reaction. Designing mutated recombinant subunits, we show that the XPB helicase is absolutely required for transcription to open the promoter around the start site whereas the XPD helicase, which is dispensable, stimulates transcription and allows the CAK complex to be anchored to TFIIH. In addition, we also show that cdk7 may phosphorylate the carboxy-terminal domain (CTD) of RNA pol II in the absence of promoter opening.
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