title: Characterization of Ribosomal Frameshifting in Theiler's Murine Encephalomyelitis Virus.
abstract: Theiler's murine encephalomyelitis virus (TMEV) is a member of the genus Cardiovirus in the Picornaviridae, a family of positive-sense single-stranded RNA viruses. Previously, we demonstrated that in the related cardiovirus, Encephalomyocarditis virus, a programmed-1 ribosomal frameshift (1 PRF) occurs at a conserved G_GUU_UUU sequence within the 2B-encoding region of the polyprotein open reading frame (ORF). Here we show that-1 PRF occurs at a similar site during translation of the TMEV genome. In addition, we demonstrate that a predicted 3= RNA stem-loop structure at a noncanonical spacing downstream of the shift site is required for efficient frameshifting in TMEV and that frameshifting also requires virus infection. Mutating the G_GUU_UUU shift site to inhibit frameshifting results in an attenuated virus with reduced growth kinetics and a small-plaque phenotype. Frameshifting in the virus context was found to be extremely efficient at 74 to 82%, which, to our knowledge, is the highest frameshifting efficiency recorded to date for any virus. We propose that highly efficient-1 PRF in TMEV provides a mechanism to escape the confines of equimolar expression normally inherent in the single-polyprotein expression strategy of picornaviruses.
authors.forename: Leanne K
authors.initials: LK
authors.lastname: Finch
authors.forename: Roger
authors.initials: R
authors.lastname: Ling
authors.forename: Sawsan
authors.initials: S
authors.lastname: Napthine
authors.forename: Allan
authors.initials: A
authors.lastname: Olspert
authors.forename: Thomas
authors.initials: T
authors.lastname: Michiels
authors.forename: Cécile
authors.initials: C
authors.lastname: Lardinois
authors.forename: Susanne
authors.initials: S
authors.lastname: Bell
authors.forename: Gary
authors.initials: G
authors.lastname: Loughran
authors.forename: Ian
authors.initials: I
authors.lastname: Brierley
authors.forename: Andew E
authors.initials: AE
authors.lastname: Firth
mesh_terms: D000818:Animals; D002460:Cell Line; D018965:Frameshifting, Ribosomal / Q000235:genetics*; D015151:Immunoblotting; D008156:Luciferases; D013058:Mass Spectrometry; D051379:Mice; D016296:Mutagenesis; D011995:Recombination, Genetic / Q000235:genetics; D012394:Rosaniline Dyes; D017945:Theilovirus / Q000235:genetics*; D010948:Viral Plaque Assay
chemical_list: D012394:Rosaniline Dyes; C048139:Coomassie blue; D008156:Luciferases