Tissue-specific Forkhead protein FOXA2 up-regulates SOX14 gene expression.
The expression of Sox14 gene in spinal cord explants was found to be regulated by Sonic hedgehog (SHH) in a dose-dependent manner, indicating that this signaling molecule might act as a regulator of Sox14-expressing interneuron differentiation. In the present study we identified the positive control element and provided the first evidence that FOXA2 is involved in up-regulation of SOX14 expression in HepG2 and U87MG cell lines. By functional analysis we demonstrated that mutation in FOXA2 binding site reduced the SOX14 reporter construct activity, and that FOXA2 over-expression increased endogenous SOX14 protein expression. Further, we have shown that human SOX14 expression is GLI1 dependent in U87MG cells and SHH-N dependent in U87MG and HepG2 cell lines. By applying siRNA silencing of FOXA2, we have demonstrated that upregulation of endogenous SOX14 gene expression by SHH is, at least in part, mediated by FOXA2. However, our data revealed that a positive regulatory region, containing functional FOXA2 site analyzed in this study, is not involved in mediation of SHH dependent SOX14 activation. Data presented here provide the initial insight into molecular mechanism underlying tissue and developmentally specific regulation of the SOX14 gene expression.
Popovic
Jelena
J
University of Belgrade, Vojvode Stepe, 11010 Belgrade, Serbia.
Klajn
Andrijana
A
Petrovic
Isidora
I
Stevanovic
Milena
M
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism; D051542:Hepatocyte Nuclear Factor 3-beta / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D016297:Mutagenesis, Site-Directed; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D055749:SOXB2 Transcription Factors / Q000235:genetics*; D014018:Tissue Distribution; D014162:Transfection; D015854:Up-Regulation; D000071676:Zinc Finger Protein GLI1
D017931:DNA Primers; C496502:FOXA2 protein, human; C498520:Gli1 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C117478:SOX14 protein, human; D055749:SOXB2 Transcription Factors; C465570:Shh protein, mouse; D000071676:Zinc Finger Protein GLI1; D051542:Hepatocyte Nuclear Factor 3-beta