Figure 4

ADAM10 down-regulation inhibits Tat-dependent HIV-1 replication steps. (A) ADAM10 down-regulation with siRNA affects Tat-dependent β-galactosidase production in U373-MAGI-CCR5 cells after infection with HIV-SF162. β-galactosidase was measured by fluorescence at various time points after infection (**P < 0.01). (B) ADAM10 does not directly activate Tat. After either ADAM10 or ERBB2IP down-regulation, U373-MAGI-CCR5 cells were transfected with a plasmid encoding recombinant Tat, indicating that ADAM10 affects virus replication prior to Tat transcription or translation. β-galactosidase is expressed as RLUs (Relative Light Units). (C) ADAM10 down-regulation significantly reduces HIV p24 production in virally infected but not HIV plasmid-transfected TZM-bl cells. ADAM10 down-regulation affected viral replication in HIV-NL4-3 infected cells, but not in cells transfected with pNL4-3, a plasmid expressing the full length NL4-3 molecular clone (*P < 0.05) (D) Diagram illustrating the different processes for virus production in the virus vs plasmid experiment. Viral mRNA can be directly transcribed from the pNL4-3 plasmid, while virus infection must go through entry, reverse transcription, nuclear entry, and integration to produce viral RNA.