The white spot syndrome virus DNA genome sequence

White spot syndrome virus (WSSV) is at present a major scourge to worldwide shrimp cultivation. We have determined the entire sequence of the double-s tranded, circular DNA genome of WSSV, which contains 292,967 nucleotides en compassing 184 major open reading frames (ORFs). Only 6% of the WSSV ORFs h ave putative homologues in databases, mainly representing genes encoding en zymes for nucleotide metabolism, DNA replication, and protein modification. The remaining ORFs are mostly unassigned, except for five, which encode st ructural virion proteins. Unique features of WSSV are the presence of a ver y long ORF of 18,234 nucleotides, with unknown function, a collagen-like OR F, and nine regions, dispersed along the genome, each containing a variable number of 250-bp tandem repeats. The collective information on WSSV and th e phylogenetic analysis on the viral DNA polymerase suggest that WSSV diffe rs profoundly from all presently known viruses and that it is a representat ive of a new virus family. (C) 2001 Academic Press.