Screening the optimal activity region of the dopachrome tautomerase gene promoter in sheep skin melanocytes.

To determine the optimal activity region of the dopachrome tautomerase gene (DCT) promoter in sheep skin melanocytes, five eukaryotic expression vectors were constructed containing DCT promoter fragments of different lengths (441 bp, 652 bp, 834 bp, 1155 bp, and 1504 bp) ligated to the pLV.ExSi.P/Puro-mouse DCT-eGFP vector. These constructs were transiently transfected into sheep skin melanocytes using liposome transfection technology. GFP (Green Fluorescent Protein) expression varied among the groups transfected with different constructs as follows: 652 bp > 834 bp > 441 bp > 1504 bp > 1155 bp. GFP expression was significantly higher in the 652 bp and 834 bp groups than in the 1155 bp group (p < 0.01), while expression in the 652 bp group was significantly higher than in the 1504 bp group (p < 0.05). Additionally, we identified elements participating in the initiation of gene transcription (a CAAT box), cell type-specific expression (M-box), and the regulation of gene expression (E-box) in the sheep DCT promoter. In conclusion, the optimal active region of the sheep DCT promoter is located between -593 bp and + 41 bp. [ABSTRACT FROM AUTHOR]