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Mol Cell Biol, March 1998, p. 1467-1476, Vol. 18, No. 3
Department of Molecular Biology, The Scripps
Research Institute, La Jolla, California 92037
Received 4 August 1997/Returned for modification 3 October
1997/Accepted 15 December 1997
Nuclear transcription is repressed when eukaryotic cells enter
mitosis. Mitotic repression of transcription of various cellular and
viral gene promoters by RNA polymerase II can be reproduced in vitro
either with extracts prepared from cells arrested at mitosis with the
microtubule polymerization inhibitor nocodazole or with nuclear
extracts prepared from asynchronous cells and the mitotic protein
kinase cdc2/cyclin B. Purified cdc2/cyclin B kinase is also sufficient
to inhibit transcription in reconstituted transcription reactions with
biochemically purified and recombinant basal transcription factors and
RNA polymerase II. The cyclin-dependent kinase inhibitor
p21Waf1/Cip1/Sdi1 can reverse the effect of
cdc2/cyclin B kinase, indicating that repression of transcription is
due to protein phosphorylation. Transcription rescue and inhibition
experiments with each of the basal factors and the polymerase suggest
that multiple components of the transcription machinery are inactivated
by cdc2/cyclin B kinase. For an activated promoter, targets of
repression are TFIID and TFIIH, while for a basal promoter, TFIIH is
the major target for mitotic inactivation of transcription. Protein
labeling experiments indicate that the p62 and p36 subunits of TFIIH
are in vitro substrates for mitotic phosphorylation. Using the
carboxy-terminal domain of the large subunit of RNA polymerase II as a
test substrate for phosphorylation, the TFIIH-associated kinase,
cdk7/cyclin H, is inhibited concomitant with inhibition of
transcription activity. Our results suggest that there exist multiple
phosphorylation targets for the global shutdown of transcription at
mitosis.
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Repression of TFIIH Transcriptional Activity
and TFIIH-Associated cdk7 Kinase Activity at Mitosis

and
*
Corresponding author. Mailing address: Department of
Molecular Biology, The Scripps Research Institute, 10550 N. Torrey
Pines Rd., La Jolla, CA 92037. Phone: (619) 784-8913. Fax: (619)
784-8965. E-mail: joelg{at}scripps.edu.
Present address: Baxter Pharmaceuticals, Neuchatel, Switzerland.
Present address: Department of Structural Biology, St. Jude
Children's Research Hospital, Memphis, TN 38105.
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