Replication and expression of thymidine kinase and human globin genes microinjected into mouse fibroblasts.

Abstract

A mixture of 2 recombinant plasmids was microinjected into mouse thymidine kinase-deficient fibroblasts (L cells). One plasmid contained the thymidine kinase gene of herpes simplex virus type I and the other contained the human .beta.-globin gene. Approximately 1 or 20 copies of each plasmid were injected. Seven fibroblast colonies arising from injected cells incubated in hypoxanthine/aminopterin/thymidine medium were analyzed. These microinjected cells produced functionally active herpes simplex type I thymidine kinase enzyme, replicated the human .beta.-globin gene and produced human .beta.-globin mRNA sequences at low levels. The genetic defect (lack of thymidine kinase activity) was corrected by the microinjected thymidine kinase gene and a coinjected human .beta.-globin gene was replicated and weakly expressed.