Analysis of terminal structures of RNA from potato virus X

The 5'-end structure of potato virus X RNA was determined following enzymatic methylation in vitro. A single 3H-methyl group was introduced into the 2'-position of the 5'-penultimate residue and the end structure was determined as m7GpppG(m)pAp(Xp)3G. This part of the RNA apparently is involved in binding to ribosomes since it can be partially protected against RNase digestion by wheat germ 40S ribosomes. PVX RNA was not retained by poly(U)-sepharose, indicating that it does not contain a 3'-terminal poly(A) tract.

Nucleotide sequence and secondary structure of potato spindle tuber viroid

The viroid of the potato spindle tuber disease (PSTV) is a covalently closed ring of 359 ribonucleotides. As a result of intramolecular base pairing, a serial arrangement of double-helical sections and internal loops form a unique rod-like secondary structure. PSTV is the first pathogen of a eukaryotic organism for which the complete molecular structure has been established.

Homologous nucleotide sequences between prokaryotic and eukaryotic mRNAs: the 5'-end sequence of the mRNA of the lipoprotein of the Escherichia coli outer membrane

The sequence of the first 89 nucleotides at the 5' end of the mRNA for the lipoprotein of the Escherichia coli outer membrane is: GCUACAUGGAGAUUAACUCAAUCU-AGAGGGUAUUAAUAAUGAAAGCUACUAAACUGGUACU-GGGCGCGGUAAUCCUGGGUUCUACUCUG. The sequence of the first 72 nucleotides was established by direct sequencing methods and was extended to 89 residues on the basis of the known sequences of oligonucleotides obtained from complete digestion of the mRNA by ribonuclease T1 or A and the known amino acid sequence of the prolipoprotein. The mRNA has an untranslated region of 38 residues before the initiation codon, AUG. A unique feature of the 5'-end sequence of the mRNA is that the sequence of 12 nucleotides (GUAUUAAUAAUG) prior to, and including, the initiation codon is the same as that found at the ribosome-binding site for 80S ribosomes in brome mosaic virus RNA4, a eukaryotic mRNA [Dasgupta, R., Shih, D., Saris, C. & Kaesberg, P. (1975) Nature 256, 624-628].

Genetic complementation between natural strains of red clover mottle virus

Three strains of red clover mottle virus were purified and their components separated by density gradient and isopycnic centrifugation. The infectivity of the purified components and of homologous and heterologous mixtures of them was assayed using Phaseolus vulgaris. Infectivity enhancement occurred in all combinations of middle and bottom components. Local lesion isolates from heterologous combinations were propagated and their symptoms on Pisum sativum and Chenopodium quinoa are described. It was concluded that symptoms on both host species are determined by the middle component. Top component formation appeared to be influenced by both bottom and middle components.

Nucleotide sequence of 5' terminus of alfalfa mosaic virus RNA 4 leading into coat protein cistron

The sequence of the 5'-terminal 74 nucleotides of alfalfa mosaic virus RNA 4, the mRNA for the viral coat protein, has been deduced by using various new techniques for labeling the RNA at the 5' end with 32P and for sequencing the 5'-32P-labeled RNA. The sequence is NpppGUUUUUAUUUUUAAUUUUCUUUCAAAUACUUCCAUCAUGAGUUCUUCACAAAAGAAAGCUGGUGGGAAAGCUGG. The AUG initiator codon is located 36 nucleotides in from the 5' end; the nucleotide sequence beyond corresponds to the amino acid sequence of the coat protein. This 5' noncoding region is rich in U (58% U); except for the 5'-terminal G, the next G in is part of the initiator AUG codon.

Properties of the Mentha strain of lychnis ringspot virus

A hordeivirus isolated from horsemint (Mentha longifolia Huds.) was designated as the mentha strain of lychnis ringspot virus (LRSV-M) on the basis of serological relationship with the type strain (LRSV-T) and similarities in nucleotide sequence and properties of genomic and replicative RNAs of the two strains. Four ssRNAs in addition to the three genomic RNAs were encapsidated by LRSV-M coat protein. No genomic sequence similarity was detected between LRSV-M and either barley stripe mosaic or poa semilatent viruses under high stringency conditions, confirming that the hordeiviruses are a group of morphologically similar, but genomically distinct viruses.