THE P15(GAG) AND P12(GAG) REGIONS ARE BOTH NECESSARY FOR THE PATHOGENICITY OF THE MURINE AIDS VIRUS

The defective murine AIDS (MAIDS) virus has unique sequences in its p1 5(gag) and p12(gag) regions. To clarify whether these sequences are re sponsible for the development of MAIDS, we constructed recombinant vir uses by replacing various regions of the gag gene of the nonpathogenic replication-competent LP-BM5 ecotropic virus with those of the MAIDS virus. Recombinants containing both unique sequences of the MAIDS viru s were replication defective and induced MAIDS. However, a recombinant containing either the p15(gag) or p12(gag) region of the MAIDS virus was also replication defective but nonpathogenic in mice. A recombinan t virus containing only the p30(gag) region of the MAIDS virus was rep lication competent and nonpathogenic. These results indicate that the p15(gag) and p12(gag) regions of the MAIDS virus do not function like those of replication-competent viruses and that both of the unique seq uences in the p15(gag) and p12(gag) regions are required to develop MA IDS.