Structure and transcription of the glycoprotein gene of attenuated HEP-Flury strain of rabies virus.

The mRNA-encoding G protein of the attenuated HEP-Flury strain of rabies virus was sequenced by the cDNA cloning technique. The G-mRNA was composed of 2059 nucleotides, with the coding region located from the 28th to 1602nd nucleotide, and was capable of encoding a polypeptide of 524 amino acids. Although the coding region was highly homologous (90% or more) to that of ERA and PV strains, the 3' noncoding region of the HEP virus G-mRNA was longer than that reported for other strains by some 400 nucleotides. The extra sequence was homologous to the long G-L intergenic sequence of the PV viral genome. The HEP virus genome lacked the postulated polyadenylating signal (TG-AAAAAAAA) that should have been found just before the "long G-L intergenic region," which indicates that the long G-L intergenic region of the HEP virus is integrated into the preceding G gene, and is transcribed only as a portion of the G-mRNA molecule. In the ERA virus-infected cells, however, two species of G-mRNA (1.9 and 2.3 kb long) were produced. The longer G-mRNA also contained the sequence complementary to the long G-L intergenic region and the shorter one did not. These findings suggest that two different poly(A)-tailing signals (one is present just before and another at the end of the long G-L intergenic region) work toward terminating the transcription of the ERA virus G gene and that the longer G-mRNA is produced as a readthrough product.