Production of brown/yellow patches in the SLC7A11 transgenic sheep via testicular injection of transgene.

The gene, SLC7A11, which encodes the solute carrier family 7 member 11 (anionic amino acid transporter light chain, xCT), has been reported to be implicated in multiple processes such as in pheomelanin production, cell proliferation and migration, Kaposi's sarcoma herpesvirus (KSHV) entry into the host cells, learning and memory. Its involvement in cancer cell proliferation and metastasis has been widely studied. Its role in pheomelanogenesis is likely conserved in sheep. The full-length cDNA of sheep SLC7A11 was cloned from sheep skin fibroblasts for evaluating its role in regulating sheep coat color. The complete open reading frame of sheep xCT (sxCT) is 1512 bp in length, encoding a 503 amino acid polypeptide. We explored its function on pheomelanogenesis in vitro and in vivo. In the melan-a non-agouti mouse melanocytes that mainly produce eumelanin, overexpressed sxCT reduced the content of eumelanin. Using a testicular injection transgenic method, sxCT-transgenic sheep were generated and exhibited patches of brown/yellow coat, suggesting that sxCT can be selectively expressed to increase the pheomelanin production in wool. Our studies suggest that testicular injection of transgene can be used to genetically modify sheep coat color.