TRANSFER-RNA MIMICRY IN A NEW GROUP OF POSITIVE-STRAND RNA PLANT-VIRUSES, THE FUROVIRUSES - DIFFERENTIAL AMINOACYLATION BETWEEN THE RNA COMPONENTS OF ONE GENOME

Recent sequencing of the genomes of several furoviruses-fungus-transmi tted rod-shaped positive-strand plant viruses-has suggested the presen ce of tRNA-like structures (TLSs) at the 3' ends of the genomic RNAs. We show here that the genomic RNAs of soil-borne wheat mosaic virus (S BWMV), beet soil-borne virus (BSBV), potato mop-top virus (PMTV), pean ut clump virus (PCV), and Indian peanut clump virus (IPCV) all possess functional TLSs that are capable of high-efficiency valylation. While the SBWMV, BSBV, and PMTV TLSs are similar to those found in tymoviru ses, the PCV and I PCV TLSs harbor an insertion of about 40 nucleotide s between the two halves of the TLS. The valylated SBWMV and BSBV RNAs formed tight complexes with wheat germ EF1 alpha.GTP (K-d = 2 to 11 n M), whereas valylated PMN, PCV, and IPCV RNAs bound EF1 alpha.GTP weak ly (K-d greater than or equal to 50 nM). The TLS of PCV RNA2 differs f rom PCV RNA1 in lacking the major valine identity nucleotide in the an ticodon and consequently is capable of only very inefficient valylatio n. This is the first case of differential aminoacylation between the R NA components of one genome. (C) 1998 Academic Press.