Probing the Importance of tRNA Anticodon: Human Immunodeficiency Virus Type 1 (HIV-1) RNA Genome Complementarity with an HIV-1 That Selects tRNAGlu for Replication

摘要

The initiation of human immunodeficiency virus type 1 (HIV-1) reverse transcription occurs at the primer binding site (PBS) that is complementary to the 3′-terminal nucleotides of tRNA3Lys. Why all known strains of HIV-1 select tRNA3Lys for replication is unknown. Previous studies on the effect of altering the PBS of HIV-1 on replication identified an HIV-1 with a PBS complementary to tRNAGlu. Since the virus was not initially designed to use tRNAGlu, the virus had selected tRNAGlu from the intracellular pool of tRNA for use in replication. Further characterization of HIV-1 that uses tRNAGlu may provide new insights into the preference for tRNA3Lys. HIV-1 constructed with the PBS complementary to tRNAGlu was more stable than HIV-1 with the PBS complementary to tRNAMet or tRNAHis; however, all of these viruses eventually reverted back to using tRNA3Lys following growth in SupT1 cells or peripheral blood mononuclear cells (PBMCs). New HIV-1 mutants with nucleotides in U5 complementary to the anticodon of tRNAGlu remained stable when grown in SupT1 cells or PBMCs, although the mutants grew more slowly than the wild-type virus. Sequence analysis of the U5 region and the PBS revealed additional mutations predicted to further promote tRNA-viral genome interaction. The results support the importance of the tRNA anticodon-genome interaction in the selection of the tRNA primer and highlight the fact that unique features of tRNA3Lys are exploited by HIV-1 for selection as the reverse transcription primer.