Nucleotide Sequence at the 5' Extremity of Tobacco-Mosaic-Virus RNA. 1. The Noncoding Region (Nucleotides 1-68)

Abstract

The sequence of the 5'' noncoding region of tobacco mosaic virus RNA was determined. The noncoding region is 68 nucleotides long and is unusual in that it contains no internal guanosine residues. The long T1 oligonucleotide containing the guanosine-free tract was isolated from a T1 RNase digest of tobacco mosaic virus RNA and sequenced by labeling techniques in vitro using polynucleotide kinase. The guanosine-free tract is terminated by the 1st potential initiation codon in the RNA molecule and several lines of evidence suggest that this AUG triplet is operational in initiating viral protein synthesis. The 5''-noncoding region cannot base-pair extensively with the 3''-terminal sequence of 18-S ribosomal RNA from rabbit reticulocytes.