Complete Nucleotide Sequence and Genomic Organization of the Aedes albopictus Parvovirus ( AaPV) Pathogenic for Aedes aegypti Larvae

Abstract

We have cloned the replicative form of the Aedes albopictus parvovirus ( AaPV) genome and determined the complete sequence of the viral strand. The sequence is 4176 nucleotides (nt) in length. The first 134 nt at the 3′ end and the terminal 182 nt at the 5′ end of the viral (minus) strand can both generate by folding and annealing of complementary sequences a typical terminal T-shaped structure although they differ in their sequence. Three large open reading frames (ORFs), each one in a different frame, are present between map units (mu) 8.0 and 87.6 on the complementary (plus) strand. The left, mid (located within the left ORF), and right ORFs have potential coding capacities of 95, 41, and 40 kDa, respectively. Two potential promoters were found upstream from the left and right ORFs, at mu 7.2 and mu 60.0, respectively. Computer search for sequence homologies suggests that the left ORF very likely encodes the nonstructural NS-1 protein since it contains the highly conserved NTP-binding amino acid (aa) domain (GKRN sequence) of all parvoviruses. Comparison with other invertebrate and vertebrate parvoviruses revealed that the AaPV genome shares 77.3% nt sequence homology and between 73 and 78% aa sequence homologies with the Aedes aegypti densonucleosis virus ( Aedes DNV). Organization of both genomes was similar except that no potential ORF was found on the minus strand of Aa PV. The difference of 167 nt in length between AaPV and Aedes DNV (4009 nt) genomes is due to additional noncoding sequences located between the internal coding region and the terminal palindromes in the AaPV genome. No significant homology was found between AaPV and the two other insect parvoviruses sequenced so far, the Bombyx mori DNV (BrnDNV) and the Junonia coenia DNV (JcDNV).