SOX6 binds CtBP2 to repress transcription from the Fgf-3 promoter.

Murakami A(1), Ishida S, Thurlow J, Revest JM, Dickson C.

Author information:
(1)Department of Viral Oncology, Institute for Virus Research, Kyoto University,
Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.

Fgf-3 is expressed in a complex pattern during mouse development. Previously, an
essential regulatory element PS4A was identified in the promoter region, and
shown to bind at least three factors. To identify the transcription factor(s),
we used a yeast one-hybrid screen and obtained a novel Sox6 cDNA (SOX6D). When
introduced into cells it strongly repressed activity from both an Fgf-3 reporter
gene as well as an artificial promoter containing three PS4A elements. In situ
hybridisation analysis showed that Sox6 and Fgf-3 are co-expressed in the otic
vesicle of E9.5 mouse embryos in a mutually exclusive pattern, consistent with a
repression of Fgf-3 transcription by SOX6. To characterise additional factor(s)
involved in Fgf-3 gene repression, a yeast two-hybrid screen was used with the
N-terminal portion of SOX6D. Mouse CtBP2 cDNA clones were isolated and shown to
bind SOX6 in yeast and mammalian cells. Furthermore, mutational analysis of SOX6
showed that binding to CtBP2, and its responsiveness to this co-repressor, were
dependent on a short amino acid sequence motif PLNLSS. Co-expression studies in
NIH3T3 cells showed that SOX6 and CtBP2 co-operate to repress activity from the
Fgf-3 promoter through the enhancer element PS4A. These results show that SOX6
can recruit CtBP2 to repress transcription from the Fgf-3 promoter.

 

Auteurs Bordeaux Neurocampus