Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2011
Publication Date: N/A
Technical Abstract: Oat blue dwarf virus (OBDV) was the first marafivirus (family Tymoviridae) to be sequenced and for which an infectious clone has been reported. Although sequence data are now available for multiple marafiviruses, precise details of the expression strategy of these viruses remain undocumented. Translation experiments with OBDV suggest that a large 224-240 kDa polyprotein encoded by much of the genome is post-translationally processed into its functional components, in agreement with its tymoviral lineage. ORFs for two 21-25 kDa coat proteins (CP) are encoded near the 3’ terminus and are coterminal with the large polyprotein ORF. By analogy with tymoviruses, a marafibox is presumed to serve as a promoter for a subgenomic RNA encoding the CP, yet the expression strategy for the CPs has to date been poorly investigated. The smaller (major) CP appears to be the product of direct translation of a subgenomic RNA, while the larger (minor) CP may be a cleavage product derived from a larger precursor or also may be expressed directly from a subgenomic RNA. Using an infectious clone of OBDV, we have developed a series of mutants to dissect and analyze the OBDV CP expression strategy. Preliminary results from protoplast experiments are consistent with a coat protein expression strategy involving proteolytic cleavage to produce the minor CP and direct translation of a subgenomic RNA to produce the major CP.