EXPRESSION OF THE MURINE WILD-TYPE TYROSINASE GENE IN TRANSGENIC RABBITS

The tyrosinase gene is known to be essential for melanization and has been shown to rescue pigmentation in albino mice. Previously we have d escribed the strict copy-number-dependent expression of a murine wild- type tyrosinase gene construct over several generations in transgenic mice. In this study, we analysed the same gene construct as a marker g ene for the transmission and expression of transgenes in rabbits. Usin g an albino hybrid strain, we produced transgenic rabbits expressing t he murine tyrosinase gene. Strict correlation between integration and expression of the transgene and stable germline transmission of the in tegrated gene construct according to the Mendelian pattern of inherita nce was observed. Thus, breeding control was facilitated by simple phe notypic examination of the transgenic animals. In contrast to mice tra nsgenic for the same gene construct, tyrosinase-transgenic rabbits sho wed a greater variety in hue, intensity and extent of coat pigmentatio n, which is caused by the diversity in the loci affecting the melaniza tion. Benefits and limitations of tyrosinase as a marker gene for the detection of homozygous individuals in the albino hybrid strain used a re discussed.