In order to study the oncogenic effects of EB virus latent membrane protein,the putative oncogene product encoded by EB virus BNLF1 gene,The MT-BNLF1 gene containing the promoter of the mouse metallothionein-1 gene fused the structural gene of EBV BNLF1 gene was constructed.This gene was microinjected into the pronuclei of fertilized mouse eggs to bulid up a transgenic mouse line. The results were as follow(1).The zygote′s survial rate and birth rate were 73% and 13%,respectively.(2) After analysing the mice that developed from the microinjected eggs by southern hybridization and PCR. 8% mice carry MT-BNLF1 fusion gene. This approach was a preliminary attempt to study the onset mechanism of the nasopharyngeal carcinoma.