title: TG-interacting factor (TGIF) downregulates SOX3 gene expression in the NT2/D1 cell line.
abstract: SOX3 is a member of the Sox gene family implicated in brain formation and cognitive function. It is considered to be one of the earliest neural markers in vertebrates, playing a role in specifying neuronal fate. Recently, we have established the first link between TALE (three-amino-acid loop extension) proteins, PBX1 (pre-B-cell leukemia homeobox 1) and MEIS1 (myeloid ecotropic viral integration site 1 homologue), and the expression of the human SOX3 gene. Here we present the evidence that TGIF (TG-interacting factor) is an additional TALE superfamily member involved in the regulation of human SOX3 gene expression in NT2/D1 cells by direct interaction with the consensus binding site that is conserved in primate orthologue promoters. Functional analysis demonstrated that mutation of the TGIF binding site resulted in the activation of SOX3 promoter. TGIF overexpression downregulates SOX3 promoter activity and decreases endogenous SOX3 protein expression in both uninduced and retinoic acid (RA)-induced NT2/D1 cells. Up to now, this is the first transcription factor identified as a negative regulator of SOX3 gene expression. The obtained results further underscore the significance of TALE proteins as important transcriptional regulators of SOX3 gene expression.
authors.affiliation: Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia. mojsin@eunet.rs
authors.forename: Marija
authors.initials: M
authors.lastname: Mojsin
authors.forename: Jelena
authors.initials: J
authors.lastname: Popovic
authors.forename: Natasa
authors.initials: N
authors.lastname: Kovacevic Grujicic
authors.forename: Milena
authors.initials: M
authors.lastname: Stevanovic
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018236:Carcinoma, Embryonal / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects; D054278:Embryonal Carcinoma Stem Cells / Q000473:pathology; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D051381:Rats; D012097:Repressor Proteins / Q000378:metabolism*; D055748:SOXB1 Transcription Factors / Q000235:genetics*; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D018398:Homeodomain Proteins; D012097:Repressor Proteins; C527785:SOX3 protein, human; D055748:SOXB1 Transcription Factors; C097504:TGIF1 protein, human; D014212:Tretinoin