Davies, Jeff S., Klein, David C. and Carter, David Allan 2011. Selective genomic targeting by FRA-2/FOSL2 transcription factor: Regulation of the Rgs4 gene is mediated by a variant activator protein 1 (AP-1) promoter sequence/creb-binding protein (CBP) mechanism. Journal of Biological Chemistry 286 (17) , pp. 15227-15239. 10.1074/jbc.M110.201996 |
Abstract
FRA-2/FOSL2 is a basic region-leucine zipper motif transcription factor that is widely expressed in mammalian tissues. The functional repertoire of this factor is unclear, partly due to a lack of knowledge of genomic sequences that are targeted. Here, we identified novel, functional FRA-2 targets across the genome through expression profile analysis in a knockdown transgenic rat. In this model, a nocturnal rhythm of pineal gland FRA-2 is suppressed by a genetically encoded, dominant negative mutant protein. Bioinformatic analysis of validated sets of FRA-2-regulated and -nonregulated genes revealed that the FRA-2 regulon is limited by genomic target selection rules that, in general, transcend core cis-sequence identity. However, one variant AP-1-related (AP-1R) sequence was common to a subset of regulated genes. The functional activity and protein binding partners of a candidate AP-1R sequence were determined for a novel FRA-2-repressed gene, Rgs4. FRA-2 protein preferentially associated with a proximal Rgs4 AP-1R sequence as demonstrated by ex vivo ChIP and in vitro EMSA analysis; moreover, transcriptional repression was blocked by mutation of the AP-1R sequence, whereas mutation of an upstream consensus AP-1 family sequence did not affect Rgs4 expression. Nocturnal changes in protein complexes at the Rgs4 AP-1R sequence are associated with FRA-2-dependent dismissal of the co-activator, CBP; this provides a mechanistic basis for Rgs4 gene repression. These studies have also provided functional insight into selective genomic targeting by FRA-2, highlighting discordance between predicted and actual targets. Future studies should address FRA-2-Rgs4 interactions in other systems, including the brain, where FRA-2 function is poorly understood.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Biosciences |
Subjects: | Q Science > QD Chemistry Q Science > QH Natural history > QH301 Biology |
Uncontrolled Keywords: | AP-1 Transcription Factor; CBP; CREB; Gene Expression; Microarray; Pineal Gland; Rat; FRA-2; Rgs Gene |
Publisher: | American Society for Biochemistry and Molecular Biology |
ISSN: | 0021-9258 |
Last Modified: | 04 Jun 2017 03:31 |
URI: | https://orca.cardiff.ac.uk/id/eprint/22407 |
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