Cymbidium ringspot virus defective interfering RNA replication in yeast cells occurs on endoplasmic reticulum-derived membranes in the absence of peroxisomes.
The replication of Cymbidium ringspot virus (CymRSV) defective interfering (DI) RNA in cells of the yeast Saccharomyces cerevisiae normally takes place in association with the peroxisomal membrane, thus paralleling the replication events in infected plant cells. However, previous results with a peroxisome-deficient mutant strain of yeast had suggested that the presence of peroxisomes is not a strict requirement for CymRSV DI RNA replication. Thus, a novel approach was used to study the putative alternative sites of replication by using S. cerevisiae strain YPH499 which does not contain normal peroxisomes. In this strain, CymRSV p33 and p92 accumulated over portions of the nuclear membrane and on membranous overgrowths which were identified as endoplasmic reticulum (ER) strands, following immunofluorescence and immunoelectron microscope observations. The proteins were not released by high-pH treatment, but were susceptible to proteolytic digestion, thus indicating peripheral and not integrated association. ER-associated p33 and p92 proteins supported in trans the replication of DI RNA. The capacity of plus-strand RNA viruses to replicate in association with different types of cell membranes was thus confirmed.
Rubino
Luisa
L
Istituto di Virologia Vegetale del CNR, Sezione di Bari, c/o Dipartimento di Protezione delle Piante e Microbiologia Applicata, Università degli Studi, Bari, Italy.
Navarro
Beatriz
B
Istituto di Virologia Vegetale del CNR, Sezione di Bari, c/o Dipartimento di Protezione delle Piante e Microbiologia Applicata, Università degli Studi, Bari, Italy.
Russo
Marcello
M
Istituto di Virologia Vegetale del CNR, Sezione di Bari, c/o Dipartimento di Protezione delle Piante e Microbiologia Applicata, Università degli Studi, Bari, Italy.
D004252:DNA Mutational Analysis; D004721:Endoplasmic Reticulum / Q000648:ultrastructure / Q000821:virology*; D007425:Intracellular Membranes / Q000648:ultrastructure / Q000821:virology*; D020675:Peroxisomes / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000821:virology*; D017864:Tombusvirus / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics
D034741:RNA, Small Interfering; D012367:RNA, Viral; D014764:Viral Proteins