The complete sequence of the Cydia pomonella granulovirus genome

The nucleotide sequence of the DNA genome of Cydia pomonella granulovirus ( CpGV) was determined and analysed. The genome is composed of 123 500 by and has a G+C content of 45.2%. It contains 143 ORFs of 150 nucleotides or mor e that show minimal overlap. One-hundred-and-eighteen (82.5%) of these puta tive genes are homologous to genes previously identified in other baculovir uses. Among them, 73 are homologous to genes of Autographa californica nucl eopolyhedrovirus (AcMNPV), whereas 108 and 98 are homologous to genes of Xe sda c-nigrum GV (XcGV) and Plutella xylostella GV (PxGV), respectively. The se homologues show on average 374% overall amino acid sequence identity to those from AcMNPV and 45% to those from XcGV and PxGV. The CpGV gene conten t was compared to that of other baculoviruses. Several genes reported to ha ve major roles in baculovirus biology were not found in the CpGV genome, su ch as gp64, the major budded virus glycoprotein gene in some nucleopolyhedr oviruses, and lef-7, involved in DNA replication. However, the CpGV genome encodes the large and small subunits of ribonucleotide reductase, three inh ibitor of apoptosis (iap) homologues and two protein tyrosine phosphatases. The CpGV, PxGV and XcGV genomes present a noticeably high level of conserv ation of gene order and orientation. A striking feature of the CpGV genome is the absence of typical homologous repeat sequences. However, it contains one major repeat region and 13 copies of a single 73-77 by imperfect palin drome.