Sequence of mouse hepatitis virus A59 mRNA2: Indications for RNA recombination between coronaviruses and influenza C virus

The nucleotide sequence of the unique region of coronavirus MHV-A59 mRNA 2 has been determined. Two open reading frames (ORF) are predicted: ORF1 potentially encodes a protein of 261 amino acids; its amino acid sequence contains elements which indicate nucleotide binding properties. ORF2 predicts a 413 amino acids protein; it lacks a translation initiation codon and is therefore probably a pseudogene. The authors discuss the possibility that both similarities are the result of recombinations and present a model for the acquisition and the subsequent inactivation of ORF2; the model applies also to MHV-A59-related coronaviruses in which they expect ORF2 to be still functional.