Open AccessInvolvement of Negative Cofactor NC2 in Active Repression by Zinc Finger-Homeodomain Transcription Factor AREB6
Author(s) -
Keiko Ikeda,
Joern-Peter Halle,
Gertraud Stelzer,
Michael Meisterernst,
Kiyoshi Kawakami
Publication year - 1998
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.18.1.10
Subject(s) - transcription factor ii a , biology , psychological repression , transcription factor ii b , general transcription factor , microbiology and biotechnology , transcription factor ii d , transcription factor , zinc finger , transcription preinitiation complex , transcription (linguistics) , transcription factor ii e , zinc finger transcription factor , promoter , genetics , transcriptional regulation , gene , gene expression , linguistics , philosophy
The transcription factor AREB6 contains a homeodomain flanked by two clusters of Krüppel type C2 H2 zinc fingers. AREB6 binds to the E-box consensus sequence, CACCTGT, through either the N- or the C-terminal zinc finger cluster. To gain insights into the molecular mechanism by which AREB6 activates and represses gene expression, we analyzed the domain structure of AREB6 in the context of a heterologous DNA-binding domain by transient-transfection assays. The C-terminal region spanning amino acids 1011 to 1124 was identified as a conventional acidic activation domain. The region containing amino acids 754 to 901, which was identified as a repression domain, consists of 40% hydrophobic amino acids displaying no sequence similarities to other known repression domains. This region repressed transcription in vitro in a HeLa nuclear extract but not in reconstituted transcription systems consisting of transcription factor IID (TFIID), TFIIB, TFIIE, TFIIH/F, and RNA polymerase II. The addition of recombinant negative cofactor NC2 (NC2α/DRAP1 and NC2β/Dr1) to the reconstituted transcription system restored the activity of the AREB6 repression domain. We further demonstrated interactions between the AREB6 repression domain and NC2α in yeast two-hybrid assay. Our findings suggest a mechanism of transcriptional repression that is mediated by the general cofactor NC2.