Effect of Altering the tRNA\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(_{3}^{Lys}\) \end{document}Concentration in Human Immunodeficiency Virus Type 1 upon Its Annealing to Viral RNA, GagPol Incorporation, and Viral Infectivity

Abstract

Human immunodeficiency virus type 1 (HIV-1) uses tRNA \(_{3}^{Lys}\) as a primer for reverse transcription and, during viral assembly, this tRNA is selectively packaged into the virus along with the other major tRNA^Lys, tRNA \(_{1,2}^{Lys}\) . Increasing the cytoplasmic concentration of tRNA \(_{3}^{Lys}\) through transfection of cells with a plasmid containing both HIV-1 proviral DNA and a tRNA \(_{3}^{Lys}\) gene results in a greater incorporation of tRNA \(_{3}^{Lys}\) into virions, which is accompanied by increased annealing of tRNA \(_{3}^{Lys}\) to the viral genome and increased infectivity of the viral population. Increased viral tRNA \(_{3}^{Lys}\) is accompanied by decreased viral tRNA \(_{1,2}^{Lys}\) , with the total tRNA^Lys/virion and the GagPol/Gag ratios remaining unchanged. Viral tRNA^Lys can be doubled, with increases in both tRNA \(_{3}^{Lys}\) and tRNA \(_{1,2}^{Lys}\) concentrations, by overexpressing lysyl tRNA synthetase. This also results in increased tRNA \(_{3}^{Lys}\) annealing to the viral RNA and increased viral infectivity but, again, no change in the GagPol/Gag ratio was observed. This result indicates that GagPol, whose interaction is required during packaging, is not a limiting factor during tRNA^Lys incorporation into HIV-1, whereas LysRS is.