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A Messenger RNA for Tobacco Mosaic Virus Coat Protein in Infected Tobacco Mesophyll Protoplasts
Author(s) -
Ogawa M.,
Sakai F.,
Takebe I.
Publication year - 1983
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1983.tb00062.x
Subject(s) - polysome , tobacco mosaic virus , biology , rna , protoplast , tobamovirus , microbiology and biotechnology , alfalfa mosaic virus , messenger rna , subgenomic mrna , biochemistry , virus , virology , ribosome , coat protein , gene
The low molecular weight tobacco mosaic virus (TMV)‐specific RNA component (LMC) was demonstrated in tobacco mesophyll protoplasts by polyacrylamide gel electrophoresis of 14 C‐uridine‐labelled RNA from infected protoplasts. Free and membrane‐bound polysomes were isolated from infected protoplasts, and RNA extracted from them was analyzed. TMV‐specific RNA species including full‐length viral RNA, its replicative intermediate, and LMC were found in both free and membrane‐bound polysomes, but were present in free polysomes in much larger amounts. In particular, as much as 37 % of total LMC in protoplasts was found in free polysomes. Fractionation of polysomes by sedimentation in sucrose gradients showed that LMC is associated with small‐sized polysomes (mono‐ to tetrasomes). Polysomes of this size class produced viral coat protein in a cell‐free protein synthesizing system from rabbit reticulocytes. On the other hand, full‐length TMV‐RNA was associated predominantly with larger polysomes which produced in the cell‐free system TMV‐specific high molecular weight polypeptides but no coat protein. These results indicated that LMC, a subgenomic RNA of TMV, in fact functions in vivo as messenger RNA for viral coat protein, as has been postulated on the basis of in vitro studies.