Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2003 Feb 21;278(8):5744-9. Epub 2002 Dec 10.

Hypoxia actively represses transcription by inducing negative cofactor 2 (Dr1/DrAP1) and blocking preinitiation complex assembly.

Author information

  • 1Department of Radiation Oncology, Division of Radiation and Cancer Biology, Stanford University Medical School, Stanford, California 94305-5152, USA.

Abstract

Hypoxia is a growth inhibitory stress associated with multiple disease states. We find that hypoxic stress actively regulates transcription not only by activation of specific genes but also by selective repression. We reconstituted this bimodal response to hypoxia in vitro and determined a mechanism for hypoxia-mediated repression of transcription. Hypoxic cell extracts are competent for transcript elongation, but cannot assemble a functional preinitiation complex (PIC) at a subset of promoters. PIC assembly and RNA polymerase II C-terminal domain (CTD) phosphorylation were blocked by hypoxic induction and core promoter binding of negative cofactor 2 protein (NC2 alpha/beta, Dr1/DrAP1). Immunodepletion of NC2 beta/Dr1 protein complexes rescued hypoxic-repressed transcription without alteration of normoxic transcription. Physiological regulation of NC2 activity may represent an active means of conserving energy in response to hypoxic stress.

PMID:
12477712
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk