Nucleotide sequence of coronavirus TGEV genomic RNA: evidence for 3 mRNA species between the peplomer and matrix protein genes

The region of the TGEV genome between the E1-matrix protein gene and the E2-peplomer protein gene has been sequenced from a cDNA clone. The consensus recognition sequence, 5 ′ AA TT CTAAAC was found upstream from 3 large open reading frames. In coronaviruses these homologous recognition sequences are involved in the initiation of transcription suggesting that there are 3 mRNA species in this region of the TGEV genome. Northern blot analysis and nuclease S1 mapping confirmed the presence of 3 mRNA species between mRNA 3 encoding the E2-peplomer protein and mRNA 6 encoding the E1-matrix protein. The 5′ regions of these 3 mRNAs encode potential polypeptides of predicted molecular weight; 7859, 27744 and 9287, respectively. The potential translation product of ORF B (27744 Da) is considerably larger than previously reported and could be difficult to distinguish by size from the E1-matrix protein.