In Vivo Infection of Mice by Replication-Competent MLV-Based Retroviral Vectors

The development of retroviral vectors has provided scientists with an effective way of achieving gene transfer stable over cell generations. This is possible because integration of proviral DNA into the genome of infected cells permits duplication of the ectopic genetic information at every round of DNA synthesis and, thus, transmission to daughter cells. Vectors have been derived from many sorts of parental retroviruses including simple avian and murine retroviruses, as well as mammalian lentiviruses. Nevertheless, Murine Leukemia Virus (MLV)-derived vectors have been the most widely used both in the laboratory and in the clinic ( for reviews, see refs. 1 –4 ). the retroviral vector in its pro viral form. Culture supernatants are collected and, after possible concentration of retroviruses, subsequently used for infection of cells of interest (1 –4 ).