The metabolism of SV40 RNA is associated with the cytoskeletal framework

Abstract

We prepared the cytoskeletal framework of SV40-infected BSC-1 cells late after infection by extracting the cells with Triton X-100. The cytoskeletal framework obtained by this procedure carries more than 80% of the newly synthesized viral polyribosomes. Almost all the viral-specific cytoplasmic RNA is engaged in the formation of cytoskeletal-associated polyribosomes. The cytoskeletal framework harbors both the poly(A) + 19 S and 16 S late viral RNAs, as well as most of the poly(A) − viral RNA. The poly(A) − viral RNA sediments in sucrose gradients between 4 and 18 S representing heterogeneous species and comprises about 30–50% of the total virus-specific RNA in the cytoplasm. Based on pulse-chase experiments it is concluded that: (i) the poly(A) + viral RNA emerges from the nucleus and becomes associated with the cytoskeletal framework, (ii) the decay rate of the poly(A) + RNA species on the cytoskeletal framework is faster than that of the poly(A) − viral RNA, and (iii) both the poly(A) + and poly(A) − viral RNAs detach from the cytoskeletal framework and move to the soluble fraction.