COMPLETE NUCLEOTIDE-SEQUENCE OF COLORADO TICK FEVER VIRUS SEGMENTS M6, S1 AND S2

The nucleotide sequences of the tenth (M6), eleventh (S1) and twelfth (S2) dsRNA genomic segments of the Florio strain (N-7180) of Colorado tick fever virus were determined and found to be 675, 998 and 1884 bp, respectively, in length, A nonanucleotide motif and a hexanucleotide motif were found to be highly conserved in the 5' and 3' non-coding re gions (NCRs), respectively, of the three segments. The first and last three nucleotides of each segment were of inverted complementarity, an d segment-specific inverted terminal repeats were detected in the NCRs of the three segments, These findings suggest the occurrence of intra cellular panhandle structures for the RNA transcripts. A readthrough p henomenon is suspected in segment M6. The environment surrounding the opal codon (position 1052-1054) of segment M6 conforms to that of leak y opal codons described in the literature.