Determination and comparative analysis of the small RNA genomic sequences of California encephalitis, Jamestown Canyon, Jerry Slough, Melao, Keystone and Trivittatus viruses (Bunyaviridae, genus Bunyavirus, California serogroup).

Abstract

The nucleotide sequences of the small (S) genomic RNAs of six California (CAL) serogroup bunyaviruses (Bunyaviridae: genus Bunyavirus) were determined. The S RNAs of two California encephalitis virus strains, two Jamestown Canyon virus strains, Jerry Slough virus, Melao virus, Keystone virus and Trivittatus virus contained the overlapping nucleocapsid (N) and non-structural (NSs) protein open reading frames (ORFs) as described previously for the S RNAs of other CAL serogroup viruses. All N protein ORFs were 708 nucleotides in length and encoded a putative 235 amino acid gene product. The NSs ORFs were found to be of two lengths, 279 and 294 nucleotides, which potentially encode 92 and 97 amino acid proteins, respectively. The complementary termini and a purine-rich sequence in the 3' non-coding region (genome-complementary sense) were highly conserved amongst CAL serogroup bunyavirus S RNAs. Phylogenetic analyses of N ORF sequences indicate that the CAL serogroup bunyaviruses can be divided into three monophyletic lineages corresponding to three of the complexes previously derived by serological classification. The truncated version of the NSs protein, which is found in five CAL serogroup bunyaviruses, appears to have arisen twice during virus evolution.