PB2 polymerase subunit of Thogoto virus (Orthomyxoviridae family)

Thogoto virus (THOV) represents a new genus in the family Orthomyxoviridae. The three polymerase subunits pB1, PB2, and PA initiate transcription by a unique cap-stealing mechanism that involves the cleavage of only the m(7)G pppAm structure from cellular hnRNAs. Here, we report the cloning of the lo ngest genomic segment of THOV coding for PB2. it comprises 2,375 nucleotide s encoding a single large open reading frame flanked by the conserved termi nal regions typical for orthomyxoviruses: The deduced amino acid sequence c orresponds to a protein of 769 amino acids, with an estimated Mr of 88,042. Expression of the PB2 cDNA in mammalian cells revealed nuclear accumulatio n of the recombinant protein, consistent;with the replication of THOV in th e cell nucleus.