Transgenic mice expressing human lysozyme gene in milk
Objective To study the expression properties of self-constructed mammary gland-specific expression vector p205C3. Methods Human lysozyme (hLYZ) cDNA was subcloned into p205C3 and the recombinant vector was used to generate transgenic mice. Transgene integration was detected by PCR and confirmed by Southern blotting. Tissue specificity of the transgene expression was shown by RT-PCR and the expressed product was identified by micrococcal lysis assay and Western blotting. Results A total of 136 F 0 mice were obtained, of which 4(1♀3♂) carried the transgene. Among them, the only one female founder did not express the gene of interest and four F 1 offspring of one male founder expressed hLYZ activities in their milk with the level of 5-200 μg/ml. The expression level of F 3 homozygotes was over 500μg/ml. The expression was restricted to mammary gland and the expressed protein had the same molecular weight to that of normal hLYZ. Conclusion The self-constructed vector can efficiently drive hLYZ cDNA expression in murine mammary gland and thus useful for generation of animal mammary gland bioreactors.