The Pr60(gag) protein of the murine AIDS (MAIDS) defective virus promo
tes the proliferation of the infected target B cells and is responsibl
e for inducing a severe immunodeficiency disease. Using the yeast two-
hybrid system, we identified the SH3 domain of c-Abl as interacting wi
th the proline-rich p12 domain of pr60(gag). The two proteins were sho
wn to associate in vitro and in vivo in MAIDS virus-infected B cells.
Overexpression of Pr60(gag) in these cells led to a detectable increas
e of the levels of c-Abl protein and to its translocation at the membr
ane. These results suggest that this viral protein serves as a docking
site for signaling molecules and that c-Abl may be involved in the pr
oliferation of infected B cells.