Structural elements of viral ribonucleic acid and their variation. I. An adenine-rich and strain-specific segment in tobacco mosaic virus ribonucleic acid.

Abstract

TMV RNA contains a unique long segment lacking guanylic acid residues. Chromatographical, biochemical, and physical analyses suggest a size of about 40 nucleotides with one terminal 3′-Gp. Base composition of this stretch of TMV RNA appears to be strain-specific among three wild strains, yielding a general formula of (C8A20U11) G for the case of vulgare TMV, (C8A18U12) G for dahlemense TMV, and (C8A24U6) G for the strain U2. More closely related strains within the vulgare group (vulgare, A14, Ni 462) have no difference in base composition between these segments. Some new techniques are described which helped in determining the chain length of such long oligonucleotides. A decision whether this segment contains the beginning of the coat protein cistron on the TMV RNA or not had to be postponed until the nucleotide sequence is elaborated.