Abstract
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.
Original language | English |
---|---|
Pages (from-to) | 874-881 |
Number of pages | 8 |
Journal | Journal of biochemistry |
Volume | 118 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1995 Oct |
Keywords
- Factor
- Gene regulation
- Melanogenesis
- Microphthalmia-associated transcription
- TRP-1
- Tyrosinase
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology