COMPLETE SEQUENCE (20 KILOBASES) OF THE POLYPROTEIN-ENCODING GENE-1 OF TRANSMISSIBLE GASTROENTERITIS VIRUS

The entire nucleotide sequence of cloned cDNAs containing the 5'-untra nslated region and gene 1 of Purdue-115 strain of transmissible gastro enteritis virus (TGEV) was determined. This completes the sequence of the TGEV genome, which is 28,579 nucleotides long. The gene 1 is compo sed of hive large open reading frames, ORF1a and ORF1b, which contain 4017 and 2698 codons, respectively (stop excluded). A brief, three-cod on-long ORF is present upstream of ORF1a. ORF1b overlaps ORF1a by 43 b ases in the (-1) reading frame. In Vitro experiments indicated that tr anslation of the ORF1a/b polyprotein involves an efficient ribosomal f rameshifting activity, as previously shown for other coronaviruses. An alysis of the predicted ORF1a and ORF1b translation products revealed that the putative functional domains identified in infectious bronchit is virus (IBV), mouse hepatitis virus (MHV) and human coronavirus 229E (HCV 229E) are all present in TGEV. The amino-terminal half of the OR F1a product exhibits greater divergence than the carboxy-terminal half , including within the TGEV/HCV229E pair. The ORF1b protein is overall highly conserved among the above four coronaviruses, except a diverge nt region situated near the carboxy terminus. (C) 1995 Academic Press, Inc.