Thogoto virus matrix protein is encoded by a spliced mRNA

Thogoto vints (THOV) is a tick-transmitted orthomyxovirus with a segmented, negative-stranded RNA genome. In this study, we investigated the coding st rategy of RNA segment 6 and found that it contains 956 nucleotides and code s for the matrix (M) protein. The full-length cDNA contains a single, long reading frame that lacks a stop codon but has coding capacity for a putativ e 35-kDa protein. In contrast, the M protein of THOV has an apparent molecu lar mass of 29 kDa as assessed by polyacrylamide gel electrophoresis. There fore, we investigated the possibility of posttranscriptional processing of segment 6 transcripts by reverse transcription-PCR and identified a spliced mRNA that contains a stop codon and is translated into the 29-kDa M protei n. Interestingly, the nontemplated UGA stop codon is generated by the splic ing event itself. Thus, the unusual M coding strategy of THOV resembles tha t of Influenza C virus.