title: The Red clover necrotic mosaic virus origin of assembly is delimited to the RNA-2 trans-activator.
abstract: The bipartite RNA genome of Red clover necrotic mosaic virus (RCNMV) is encapsidated into icosahedral virions that exist as two populations: i) virions that co-package both genomic RNAs and ii) virions packaging multiple copies of RNA-2. To elucidate the packaging mechanism, we sought to identify the RCNMV origin of assembly sequence (OAS). RCNMV RNA-1 cannot package in the absence of RNA-2 suggesting that it does not contain an independent packaging signal. A 209 nt RNA-2 element expressed from the Tomato bushy stunt virus CP subgenomic promoter is co-assembled with genomic RNA-1 into virions. Deletion mutagenesis delimited the previously characterized 34 nt trans-activator (TA) as the minimal RCNMV OAS. From this study we hypothesize that RNA-1 must be base-paired with RNA-2 at the TA to initiate co-packaging. The addition of viral assembly illustrates the critical importance of the multifunctional TA element as a key regulatory switch in the RCNMV life cycle.
authors.affiliation: Department of Plant Pathology, North Carolina State University, Raleigh, NC 27695-7342, USA.
authors.forename: Veronica R
authors.initials: VR
authors.lastname: Basnayake
authors.forename: Tim L
authors.initials: TL
authors.lastname: Sit
authors.forename: Steven A
authors.initials: SA
authors.lastname: Lommel
mesh_terms: D020029:Base Pairing; D036022:Capsid Proteins / Q000235:genetics; D016679:Genome, Viral; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics*; D019183:Tombusviridae / Q000235:genetics* / Q000502:physiology; D017864:Tombusvirus / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic; D029921:Trifolium / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics; D014771:Virion / Q000235:genetics / Q000502:physiology; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D012367:RNA, Viral; D015534:Trans-Activators; D014764:Viral Proteins