Intrauterine gene transfer: gestational stage-specific gene delivery in mice

Intrauterine gene transfer in mice by intraplacental microinjection of reco mbinant adenoviral or retroviral vectors carrying beta-galactosidase (beta- gal) reporter gene was analyzed in relation to gestational stage, viral tit er and promoters. After injections of viral vectors on days 9.5, 11.5 or 14 .5 post coitum (p.c.), embryos, fetuses and adult animals were analyzed for beta-gal expression on days 13.5 p.c., 18.5 p.c. and at 2 months of age, r espectively. Injection of adenoviral vectors on day 9.5 or day 11.5 p.c. re sulted in high beta-gal expression in the heart or liver, respectively. Inj ection on either day also gave expression in other tissues including vascul ature and hindbrain. This temporal pattern of adenoviral transduction corre lated with the expression level of integrin beta(3) subunit which is known to be a component involved in adenoviral transduction. Adenovirus-mediated intrauterine gene transfer resulted in persistent beta-gal expression in mu ltiple cell foci in the liver and hearts of 2-month-old adult animals treat ed in utero, indicating stable integration of the transgene into the host c ell genome at a low frequency. Although at low efficiency, injection of ret roviral vector on day 9.5 and 11.5 p.c. resulted in beta-gal expression in embryonic liver while day 9.5 p.c. injection resulted in persistent beta-ga l expression in 2-month-old adult heart. This is the first study to show ge stational stage-specific gene transfer via intraplacental microinjection of adenoviral vectors.