title: The double-stranded RNA associated with the '447' cytoplasmic male sterility in Vicia faba is packaged together with its replicase in cytoplasmic membranous vesicles.
abstract: The 447 male sterility trait in Vicia faba is strictly correlated with the presence of well-defined membranous vesicles or 'cytoplasmic spherical bodies' not found in fertile isogenic maintainer plants, and by the occurrence of a discrete high molecular weight double-stranded RNA. We have purified these cytoplasmic membranous vesicles and find that they contain the dsRNA together with an RNA-dependent RNA polymerase whose activity depends upon the presence of Mg2+, requires the four-nucleoside triphosphates and is unaffected by inhibitors of cellular transcriptases, e.g. alpha-amanitin and Actinomycin D. The dsRNA can be labelled in vitro by incubating the cytoplasmic vesicles with radioactive NTPs, and the RNA synthesized in vitro is also in a double-stranded form as judged by its resistance to RNase digestion at high salt and its behaviour upon CF-11 chromatography. Treatment of the vesicles with a non-ionic detergent releases the dsRNA in the form of a complex with the RNA-dependent RNA polymerase. The enzyme can still carry out the specific synthesis of dsRNA in these solubilized complexes. The cytoplasmic vesicles therefore isolate this vertically transmitted, self-replicating dsRNA from the cellular milieu: the possible mode of action and relevance of this novel genetic element to the 447 cytoplasmic male sterility trait are discussed.
authors.affiliation: Station d'Amélioration des Plantes, Institut National de la Recherche Agronomique, Dijon, France.
authors.forename: A
authors.initials: A
authors.lastname: Lefebvre
authors.forename: R
authors.initials: R
authors.lastname: Scalla
authors.forename: P
authors.initials: P
authors.lastname: Pfeiffer
mesh_terms: D003593:Cytoplasm / Q000378:metabolism; D007887:Fabaceae / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics / Q000378:metabolism*; D010946:Plants, Medicinal; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D012098:Reproduction / Q000235:genetics
chemical_list: D012330:RNA, Double-Stranded; D012324:RNA-Dependent RNA Polymerase