Studies on the function of the non-primer tRNAs associated with the 70 S RNA of avian myeloblastosis virus

Abstract

Significant amounts of three tRNAs are associated with the 70 S RNA of avian myeloblastosis virus (AMV). The temperatures at which they are half dissociated from the 70 S RNA in 50 mM NaCl and their respective quantities relative to 35 S RNA are: tRNA Arg, 51°C, 1.6; tRNA Lys, 57°C, 0.7 and tRNA Trp, 76°C, 1.0. Possible functions for the non-primer tRNAs (tRNA Arg and tRNA Lys) were evaluated by determining the effect of their thermal dissociation on: (a) conversion of 70 S to 35 S RNA, (b) capacity of 70 S and/or 35 S RNA to be translated in vitro, and (c) capacity of 70 S and/or 35 S RNA to be reverse transcribed in vitro. Conversion of 70 S to 35 S RNA occurred with a t m of 56°C and is consistent with the hypothesis that tRNA Lys might be involved in joining two 35 S RNA subunits to form the 70 S RNA complex. There was no indication that the association of either tRNA Arg or tRNA Lys influenced the rate or quality of translation of 70 S or 35 S RNA. A decrease in the rate at which 70 S RNA is transcribed occurs in parallel with the dissociation of tRNA Arg and tRNA Lys.