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RESEARCH PRODUCT

Membrane insertion and topology of the p7B movement protein of Melon Necrotic Spot Virus (MNSV)

Vicente PallásIsmael MingarroAna SauríLuis Martínez-gilMarçal Vilar

subject

Green Fluorescent ProteinsPlant virusBiologyTopologyEndoplasmic ReticulumGreen fluorescent proteinViral ProteinsVirologyMovement proteinIntegral membrane proteinMelon necrotic spot virusEndoplasmic reticulumCarmovirusProteïnes de membranaMembrane Proteinsbiology.organism_classificationMembrane integrationMembrane protein topologyVirusPlant Viral Movement ProteinsMovement proteinsCucurbitaceaeMembraneMembrane proteinCarmovirusMNSV

description

AbstractCell-to-cell movement of the Melon Necrotic Spot Virus (MNSV) is controlled by two small proteins working in trans, an RNA-binding protein (p7A) and an integral membrane protein (p7B) separated by an amber stop codon. p7B contains a single hydrophobic region. Membrane integration of this region was observed when inserted into model proteins in the presence of microsomal membranes. Furthermore, we explored the topology and targeting mechanisms of full-length p7B. Here we present evidence that p7B integrates in vitro into the ER membrane cotranslationally and with an Nt-cytoplasmic/Ct-luminal orientation. The observed topology was monitored in vivo by fusing GFP to the Ct of p7B, enabling the overexpression in Escherichia coli cultures. Finally, the topology of a putative p14 movement protein was established by replacing the amber stop codon located between p7A and p7B.

10.1016/j.virol.2007.06.006http://dx.doi.org/10.1016/j.virol.2007.06.006