DETERMINATION AND COMPARATIVE-ANALYSIS OF THE SMALL RNA GENOMIC SEQUENCES OF CALIFORNIA ENCEPHALITIS, JAMESTOWN-CANYON-VIRUS, JERRY-SLOUGH-VIRUS, MELAO-VIRUS, KEYSTONE-VIRUS AND TRIVITTATUS-VIRUS (BUNYAVIRIDAE, GENUS BUNYAVIRUS, CALIFORNIA SEROGROUP)

The nucleotide sequences of the small (S) genomic RNAs of six Californ ia (GAL) serogroup bunyaviruses (Bunyaviridae: genus Bunyavirus) were determined. The S RNAs of two California encephalitis virus strains, t wo Jamestown Canyon virus strains, Jerry Slough virus, Melao virus, Ke ystone virus and Trivittatus virus contained the overlapping nucleocap sid (N) and nonstructural (NSs) protein open reading frames (ORFs) as described previously for the S RNAs of other CAL serogroup viruses. Al l 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 len gths, 279 and 294 nucleotides, which potentially encode 92 and 97 amin o 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. Phylog enetic analyses of N ORF sequences indicate that the CAL serogroup bun yaviruses can be divided into three monophyletic lineages correspondin g to three of the complexes previously derived by serological classifi cation. The truncated version of the NSs protein, which is found in fi ve CAL serogroup bunyaviruses, appears to have arisen twice during vir us evolution.