Since male genital organs and gametes express mA3, and since we previously showed that mA3 deficient mice are more susceptible to MLV and MMTV [45,46,51,52], we hypothesize that mice lacking the mA3 gene (mA3-/-) will have higher virus load upon infection with LP-BM5 MLV. The gene discussed is PNMA3; the disease is infection.