Direct interaction of Sox10 with the promoter of murine Dopachrome Tautomerase (Dct) and synergistic activation of Dct expression with Mitf.
The murine dopachrome tautomerase (Dct) gene is expressed early in melanocyte development during embryogenesis, prior to other members of the tyrosinase gene family important for regulating pigmentation. We have used deletion mutants of the Dct promoter, transfections with developmentally relevant transcription factors, and gel shift assays to define transcriptional determinants of Dct expression. Deletion mutagenesis studies show that sequences within the proximal 459 nucleotides are critical for high level expression in melanocytic cells. This region of the promoter contains candidate binding sites for the transcription factors Sox10 and Mitf. Transfections into 293T and NIH3T3 cells show that Sox10 and Mitf independently activate Dct expression, and, when co-transfected, synergistically activate Dct expression. To support the notion that Sox10 acts directly upon the Dct promoter to activate gene expression, direct interaction of Sox10 was demonstrated using gel shifts of oligonucleotide probes derived from promoter sequences within the region required for Sox10-dependent induction. These results suggest that a combinatorial transcription factor interaction is important for expression of Dct in neural crest-derived melanocytes, and support a model for sequential gene activation in melanocyte development whereby Mitf, a Sox10-dependent transcription factor, is expressed initially before an early melanocyte differentiation gene, Dct, is expressed.
Jiao
Zhongxian
Z
Department of Dermatology, Henry Ford Health System, Detroit, MI, USA..
Mollaaghababa
Ramin
R
Pavan
William J
WJ
Antonellis
Anthony
A
Green
Eric D
ED
Hornyak
Thomas J
TJ
D000818:Animals; D001483:Base Sequence; D002415:Cats; D002417:Cattle; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D008544:Melanocytes / Q000201:enzymology*; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor; D008969:Molecular Sequence Data; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000502:physiology*; D051381:Rats; D055757:SOXE Transcription Factors; D016415:Sequence Alignment; D017384:Sequence Deletion; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; C497236:Mitf protein, rat; D009363:Neoplasm Proteins; D055757:SOXE Transcription Factors; C527924:Sox10 protein, mouse; C527925:Sox10 protein, rat; D014157:Transcription Factors; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase