| First Author | Rungta D | Year | 1996 |
| Journal | J Invest Dermatol | Volume | 107 |
| Issue | 5 | Pages | 689-93 |
| PubMed ID | 8875950 | Mgi Jnum | J:36078 |
| Mgi Id | MGI:83529 | Doi | 10.1111/1523-1747.ep12365578 |
| Citation | Rungta D, et al. (1996) Regulation of tyrosinase mRNA in mouse melanoma cells by alpha-melanocyte-stimulating hormone. J Invest Dermatol 107(5):689-93 |
| abstractText | Cloudman S-91 mouse melanoma cells respond to alpha-melanocyte-stimulating hormone) by demonstrating a marked increase in tyrosinase activity (O-diphenol-O2 oxidoreductase, EC 1.14.18.1). This increase is the result of increased levels of tyrosinase mRNA with a subsequent increase in tyrosinase abundance. Our studies were carried out to determine the effect of melanocyte-stimulating hormone on tyrosinase gene transcription and to measure the kinetics of the hormone-induced increase in tyrosinase mRNA. When melanoma cells were exposed continuously to melanocyte-stimulating hormone for 6 d, a large but transient increase in both tyrosinase mRNA abundance and enzyme activity were observed. The maximum increase in tyrosinase mRNA occurred 60 h after melanocyte-stimulating hormone stimulation and was followed by a decline in message levels even though cells were continuously exposed to hormone. Results of nuclear run-off transcription assays showed that melanocyte-stimulating hormone caused a slow increase in the rate of transcription of the tyrosinase gene with a maximal 6-fold stimulation occurring at 48 h. In cells treated with the ribonucleic acid synthesis inhibitor, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, tyrosinase mRNA levels decayed with a half-life of 4-5 h. This decay rate was unaffected by treatment of cells with melanocyte-stimulating hormone, indicating that the hormone does not act to stabilize tyrosinase ribonucleic acid. Inhibition of protein synthesis by treatment with cycloheximide had no effect on the melanocyte-stimulating hormone-induced increase in tyrosinase messenger ribonucleic acid levels suggesting that ongoing protein synthesis is not required for, at least, the initial stimulation of tyrosinase gene transcription by melanocyte-stimulating hormone. |
