A cis-acting element involved in mouse tyrosinase gene expression and partial purification of its binding protein.
The tyrosinase gene is specifically expressed in melanocytes. Understanding the molecular basis of tissue-specific expression of the tyrosinase gene will greatly explain the mechanisms controlling pigmentation. We report a nucleotide sequence, TGATGTATTC, located -236 base pairs upstream of the transcription start site, that enhances tyrosinase gene expression in mouse melanoma cells. The sequence is referred to as the tyrosinase element-1 (TE-1). TE-1 was protected from DNase I cleavage by pigment cell nuclear extracts but was not protected by non-pigment cell nuclear extract. Partial purification of TE-1 binding protein (TEBP-1) was performed from the B16 mouse melanoma cell nuclear extract using biotin-cellulose affinity chromatography. The affinity-purified fraction exhibited binding to the DNA fragment containing TE-1, and to a synthetic oligomer representing TE-1. UV-cross-linking indicated that the size of TEBP-1 is approximately 49 kD. TE-1 also directed enhanced CAT activity in the B16 melanoma cells but not in non-pigment cells. These data indicate that TE-1 may be an enhancer element that is responsible for pigment cell specific expression of the tyrosinase gene.
Ponnazhagan
S
S
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46202.
Kwon
B S
BS
D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D002846:Chromatography, Affinity; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D005796:Genes / Q000235:genetics*; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D004273:DNA, Neoplasm; D014442:Monophenol Monooxygenase; D015500:Chloramphenicol O-Acetyltransferase