Objective    To establish an efficient and reliable method for transgenic mouse production

we performed lentiviral vector-mediated transgenesis in mice.     Methods    The leniviral vector FUGW was packaged by co-transfection of 293FT cells with two packaging vectors

psPAX2

and pMD2.G. The two packaging vectors provide structural proteins and envelope protein respectively which are necessary for the proper package of pseudotype virus. The tire of the pseudotype virus was tested by FACS after infecting 293FT cells with the solution containing the virus particles. The virus was concentrated by high speed centrifugation

and concentrated virus solution was injected into perivitelline space of mouse 1-cell eggs. EGFP expression in pre-implantation eggs was observed under fluorescent microscope

and that in mouse body under UV light.     Results    The titre of the primary virus solution was ≥10

6

TU/ml

and that after concentration was ≥10

9

TU/ml. The concentrated virus solution efficiently infected mouse eggs after injected into the perivitelline space. On 60

84

132 h after injection

EGFP expression was observed in the injected eggs. At 24 h after injection when the majority of the injected eggs was in 2-cell stage

more than 90% of the eggs was EGFP positive under fluorescent microscope. The injected 2-cell eggs was transferred into the oviduct of pseudo-pregnant female mice

and 42.9% (12/28) of the transferred mice became pregnant. The pregnant recipient mice gave birth to 120 pups

of which 60.8% (73/120) showed visible EGFP expression under UV light. The overall transgenic mouse production efficiency (transgenic mouse/injected eggs) was 5.0% (73/1 453). The EGFP transgenic founder mice were mated with wild-type mice

and EGFP expression was detected in F1

F2 and F3 offspring

indicating that the EGFP expression can be transmitted through germline cells.     Conclusion    Lentiviral transgenesis is an efficient and reliable method to produce transgenic mice. We have established the technological system for lentiviral transgenesis in mice.