Stem-loop structure of Cocksfoot mottle virus RNA is indispensable for programmed -1 ribosomal frameshifting.
The -1 programmed ribosomal frameshifting (-1 PRF) mechanism utilized by many viruses is dependent on a heptanucleotide slippery sequence and a downstream secondary structure element. In the current study, the RNA structure downstream from the slippery site of cocksfoot mottle sobemovirus (CfMV) was proven to be a 12bp stem-loop with a single bulge and a tetranucleotide loop. Several deletion and insertion mutants with altered stem-loop structures were tested in wheat germ extract (WGE) for frameshifting efficiency. The impact of the same mutations on virus infectivity was tested in oat plants. Mutations shortening or destabilizing the stem region reduced significantly but did not abolish -1 PRF in WGE. The same mutations proved to be deleterious for virus infection. However, extending the loop region to seven nucleotides had no significant effect on frameshifting efficiency in WGE and did not hamper virus replication in infected leaves. This is the first report about the experimentally proven RNA secondary structure directing -1 PRF of sobemoviruses.
Tamm
Tiina
T
Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia.
Suurväli
Jaanus
J
Lucchesi
Jimmy
J
Olspert
Allan
A
Truve
Erkki
E
D000595:Amino Acid Sequence; D018554:Avena / Q000821:virology; D001483:Base Sequence; D018965:Frameshifting, Ribosomal; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009690:Nucleic Acid Conformation; D010942:Plant Viruses / Q000472:pathogenicity / Q000502:physiology*; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics*; D017384:Sequence Deletion; D014764:Viral Proteins / Q000096:biosynthesis
D012367:RNA, Viral; D014764:Viral Proteins