Incorporation of tRNA into normal and mutant HIV-1

Abstract

During retroviral assembly, tRNAs are incorporated into the virion, one of which serves as a primer for the reverse transcription reaction. Using two dimensional polyacrylamide gel electrophoresis, we have studied the patterns of tRNAs incorporated into HIV-1 (3B) produced either in the lymphoid cell line H-9 or in the monocytic cell line U937. We have also examined viral tRNA patterns incorporated in a non-infectious, mutant virion which lacks pol gene products and processed gag protein. Our results lead to the following conclusions: 1) tRNA incorporated into HIV-1 is a select subpopulation of the host-cell's tRNA. 2) The type of tRNA incorporated into the virion is dependent upon cell type. 3) There can be multiple species of tRNA of similar mobilities tightly associated to the viral genome. 4) The packaging of putative primer tRNA into virions requires either the synthesis of pol gene products, the processing of gag proteins, or both, while the incorporation of non-primer tRNAs does not.