SOX6 binds CtBP2 to repress transcription from the Fgf-3 promoter.
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.
Murakami
A
A
Department of Viral Oncology, Institute for Virus Research, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
Ishida
S
S
Thurlow
J
J
Revest
J M
JM
Dickson
C
C
D000429:Alcohol Oxidoreductases; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007758:Ear, Inner / Q000196:embryology / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics; D051518:Fibroblast Growth Factor 3; D005346:Fibroblast Growth Factors / Q000032:analysis / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000235:genetics; D055755:SOXD Transcription Factors; D016415:Sequence Alignment; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics*; D020798:Two-Hybrid System Techniques
D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins; C489197:Fgf3 protein, mouse; D051518:Fibroblast Growth Factor 3; D006609:High Mobility Group Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D055755:SOXD Transcription Factors; C095939:Sox6 protein, mouse; D014157:Transcription Factors; D005346:Fibroblast Growth Factors; D000429:Alcohol Oxidoreductases; C111341:Ctbp2 protein, mouse