Nucleic Acids Research Advance Access originally published online on November 19, 2007
Nucleic Acids Research 2008 36(1):263-283; doi:10.1093/nar/gkm969
Nucleic Acids Research, 2008, Vol. 36, No. 1 263-283
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Molecular Biology |
SUMO1 negatively regulates BRCA1-mediated transcription, via modulation of promoter occupancy
1Department of Biological Sciences & Department of Molecular Science and Technology Ajou University, Suwon and 2Seoul National University, Seoul, Korea
*To whom correspondence should be addressed. Tel: 82 31 219 1886; Fax: 82 31 219 1615; Email: jsjlee{at}ajou.ac.kr
Received March 22, 2007. Revised October 17, 2007. Accepted October 19, 2007.
BRCA1, a tumor suppressor gene, is implicated in the repression and activation of transcription via interactions with a diverse range of proteins. The mechanisms regulating the action of BRCA1 are not fully understood. Here, we use the promoters of Gadd45
, p27KIP1 and p21WAF1/CIP1 to demonstrate that SUMO1 represses transactivation potential of BRCA1 by causing BRCA1 to be released from the promoters and augmenting histone deacetylation via recruitment of histone deacetylase (HDAC) activity. Consistently, silencing of SUMO1 led to recruitment of BRCA1 and release of HDAC1 at the BRCA1 target promoters, and subsequent transcriptional activation of the BRCA1 target genes. Furthermore, a sumoylation-incompetent mutant missing the sumoylation donor site suppressed BRCA1-induced activation of transcription, whereas E2 UBC9 or the dominant-negative mutant UBC9 had no effect, implying that repression of BRCA1-mediated activation of transcription by SUMO1 is independent of sumoylation. Repression of BRCA1-mediated activation of transcription by SUMO1 was reversed by DNA damage by inducing the release of SUMO1 from the Gadd45
promoter and the recruitment of BRCA1, along with increased histone acetylation, to enhance activation of transcription. Together, our data provide evidence that SUMO1 plays a role in the activation-repression switch of BRCA1-mediated transcription via modulation of promoter occupancy.