Abstract: Objective To generate recombinant Plasmodium yoelii BY265 strain which can express green fluorescent protein （GFP） in erythrocytic and mosquito stages. Methods Recombinant plasmid containing P. berghei ssu-rrna and GFP genes were linearized by SacⅡ. The linearized plasmid was introduced into the erythrocytic stage of P. yoelii by electroporation. Kunming mice were infected with the recombinant parasites. After 24-30 hours post-infection, mice were treated with 70 μg/ml of pyrimethamine intraperitoneally for 5-6 d, and tail vein blood was then collected to make smear for parasite count. The parasites were examined by PCR. Anopheles stephensi mosquitoes were used to bite mice infected with the recombinant parasite. At the 7th and 16th day after the bite, oocyst development in mosquitoes was observed by fluorescence microscopy. Results The recombinant parasites expressed GFP in erythrocytic stage, and the GFP and ssu-rrna genes were amplified by PCR in the recombinant parasites. The mosquito infection experiment showed a normal development of the recombinant parasites. Conclusion Transgenic P. yoelii BY265 strain has been established with stable expression of GFP in both erythrocytic and mosquito stages.

Key words: Mosquito stage, Erythrocytic stage, GFP, Plasmodium yoelii