First Author | Yasumoto K | Year | 1995 |
Journal | J Biochem | Volume | 118 |
Issue | 5 | Pages | 874-81 |
PubMed ID | 8749302 | Mgi Jnum | J:30171 |
Mgi Id | MGI:77685 | Doi | 10.1093/jb/118.5.874 |
Citation | Yasumoto K, et al. (1995) Transcriptional activation of the melanocyte-specific genes by the human homolog of the mouse Microphthalmia protein. J Biochem 118(5):874-81 |
abstractText | Mi protein encoded at the mouse microphthalmia (mi) locus is a transcription factor with a basic helix-loop-helix/leucine zipper structure. To assess the function of the human homolog of Mi protein, termed microphthalmia-associated transcription factor (MITF), we analyzed the effects of MITF on the promoter function of the mouse tyrosinase and tyrosinase-related protein 1 (TRP-1) genes. These two gene promoters are able to direct transcription preferentially in melanin-producing cells, and an enhancer element M box of 11 bp, containing a CATGTG motif, is conserved in both promoters. By transient expression assays, we have localized the cis-acting element of the tyrosinase gene responsible for pigment cell-specific expression to the proximal 82-bp region, which contains a CATGTG motif (positions -12 to -7) but lacks the M box (positions -107 to -97). We also provide evidence that the 82-bp region and the M box are involved in the transactivation of the tyrosinase promoter by MITF and that the M box is bound by MITF in vitro. Furthermore, MITF activated the TRP-1 gene promoter possibly through the M box (positions -44 to -34). These results suggest that MITF is a common factor regulating transcription of the pigment cell-specific genes. |