Journal of Plant Pathology (2007) 89, p. S21 (Rubino et al.)

L. Rubino and M. Russo (2007)
cymbidium ringspot virus replicase proteins are targeted to endoplasmic reticulum-derived membranes in the absence of peroxisomes in yeast cells
Journal of Plant Pathology 89 (3, Suppl.), S21-S21
Oral Presentation at S.I.Pa.V XIV National Meeting - Perugia, Italy 19-21 Sept. 2007
Abstract: 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, by using the peroxisome-deficient yeast strain YPH499, it was shown that the presence of peroxisomes is not a strict requirement for CymRSV DI RNA replication. In fact, in the absence of peroxisomes, CymRSV replicase proteins p33 and p92 are targeted to the endoplasmic reticulum (ER) and support a robust replication of DI RNA. Membrane floatation gradient analysis of fractionated protein extracts showed that both proteins were present in the membrane-enriched fraction, thus indicating a true association with ER rather than protein aggregation. The proteins were not released by high-salt and highpH treatment, suggesting an integrated association with membranes. However, since no protease-resistant fragment was detected, it is suggested that the proteins are peripherally associated to the cytoplasmic side of the ER with no lumenal protrusion. The specific function of the different domains contained in the CymRSV p33 protein was investigated using a series of mutants, either fused to GFP or to the Myc tag. It was shown that the ERtargeting signal is composed by multiple recognition sequences in the N-terminal region of p33, including an amphipathic helix upstream of two transmembrane domains.
Database assignments for author(s): Luisa Rubino

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tombusvirus cymbidii