THE GENOMIC 5'-TERMINUS OF MANCHESTER CALICIVIRUS

An enteric calicivirus showing the classic cup-shaped surface morpholo gy was identified in a stool sample obtained from a child with symptom s of acute gastroenteritis (Portishead virus, PHV). Genomic RNA was ex tracted directly from the PHV stool sample and amplified by RT-PCR usi ng primers based on the Manchester isolate of HuCV, The 3' terminus of the cDNA was defined by homopolymer tailing with dATP and revealed an additional 165 nucleotides suggesting that the previously determined Manchester HuCV (MV) genome sequence was incomplete. Homopolymer taili ng of MV cDNA primed using sequence data from the 5' terminus of PHV a llowed extension of the MV genome by a further 165 nucleotides thereby increasing the overall genome length to 7431 nucleotides and resultin g in an additional 72 amino acids at the N-terminus of the polyprotein , A conserved sequence motif typical of other caliciviruses was also i dentified at the extreme 5'-terminus of the genome.