Abstract: Objective To construct a plasmid for fusion expression of rsp3111 protein and fluorescent protein, and to express rSP3111 protein in IVF embryos and in mature sperms in epididymis. Methods Expression plasmid pDsRed-Monomer-Nl -rSP3 111 was constructed by subcloning the cDNA of rSP3111 protein pDsRed-Monomer-Nl. Mouse sperms were transfected by expression plasmid pDsRed-Monomer-Nl-rSP3111 by liposome-mediated methods, and fertilized with mature eggs. Alternatively, pDsRed-Monomer-Nl -rSP3 111 plasmid were introduced into testis by liposome-mediated injection. The expression level and pattern of rSP3111 protein was examined by PCR assay and fluorescent microscopy. Results The result of PCR assays confirmed that rsp3111 gene was successfully tranfered into the sperms in epididymis and into fertilized eggs. The results of fluorescent microscopy shows the specific expression of rsp3111gene both in IVF embryos and in convoluted seminiferous tubules of the testis. Conclusion Specific expression of rat gamete-specific protein rSP3111 was achieved through sperm-mediated trasnfection, which undermines the establisment of rsp3 111 trangenic mouse through in vivo transfection of spermatogonial stem cells.

Key words: in vivo transfection of spermatogonial stem cells, Gamete-specific rsp3 111 gene, in vitro fertilization