EXPRESSION OF CAPRINE BETA-LACTOGLOBULIN IN THE MILK OF TRANSGENIC MICE

A 14.5 kb-long transgene containing the complete caprine beta-lactoglo bulin gene transcription unit as well as 6.1 kb and 3.7 kb of the 5'- and 3'-flanking regions, respectively, was microinjected into pronucle ar stage mouse embryos. Four lines of transgenic mice were obtained, t hree of them expressing the transgene in their mammary glands during l actation. Western blot analysis of caprine beta-lactoglobulin in the m ilk of hemizygous transgenic animals demonstrated the presence of the exogenous protein at concentrations up to 0.5 mg ml(-1) of mouse milk.