Profiling non-lysyl tRNAs in HIV-1

During its assembly, human HIV-1 selectively packages the tRNA(Lys) isoacceptors, including tRNA(Lys3), the primer for the reverse transcriptase. However, other low molecular weight RNA species are also seen in the virus. We profiled the tRNAs packaged into HIV-1 using microarray analysis and validated our results by two-dimensional gel electrophoresis and RT-PCR. In addition to tRNA(Lys) isoacceptors, tRNA(Asn) and the rare isoacceptor of tRNA(Ile) are also selectively packaged. In Gag viral-like particles missing the GagPol protein, overall tRNA incorporation is reduced by > 80%. This reduction is significantly greater than can be accounted for by the reduction in tRNA(Lys) isoacceptors, tRNA(Asn) and tRNA(Ile), suggesting that incorporation of other tRNAs may also require the GagPol protein. These results demonstrate selective incorporation of non-lysyl tRNAs into HIV-1 and highlight the application of microarrays as a novel method to study tRNA incorporation into viruses.