Infectious Hypodermal and Hematopoietic Necrosis Virus of Shrimp Is Related to Mosquito Brevidensoviruses

Abstract

We purified and sequenced infectious hypodermal and hematopoietic necrosis virus (IHHNV), a small DNA virus of shrimp, from wild Penaeus stylirostris. The virion has a buoyant density of 1.45 as determined by cesium chloride gradient. Analysis of 3873 nucleotides of the viral genome revealed three large open reading frames (ORFs) and parts of the noncoding termini of the viral genome. The left, mid, and right ORFs on the complementary (plus) strand have potential coding capacities of 666 amino acids (aa) (75.77 kDa), 363 aa (42.11 kDa), and 329 aa (37.48 kDa), respectively. The overall genomic organization is similar to that of the mosquito brevidensoviruses. The left ORF most likely encodes the major nonstructural (NS) protein (NS-1) since it contains conserved replication initiator motifs and NTP-binding and helicase domains similar to those in NS-1 from all other parvoviruses. The IHHNV putative NS-1 shares the highest aa sequence homology with the NS-1 of mosquito brevidensoviruses, Aedes densovirus and Aedes albopictus parvovirus. A search for putative splicing sites revealed that the N-terminal region of NS-1 is very likely located in a small ORF upstream of the left ORF. The right ORF is presumed to encode structural polypeptides (VPs), as in other parvoviruses. Two putative promoters, located upstream of the left and right ORFs, are presumed to regulate expression of NS and VP genes, respectively. Thus, IHHNV is closely related to densoviruses of the genus Brevidensovirus in the family Parvoviridae, and we therefore propose to rename this virus Penaeus stylirostris densovirus (PstDNV).

Transgene expression in Penaeus monodon cells: evaluation of recombinant baculoviral vectors with shrimp specific hybrid promoters

“…Dhar et al (2007) demonstrated transient expression of luciferase under the control of P2 promoter in the constructed vector P2 complete pGL3, even though the results were variable. Because, it is located near map unit 2, Shike et al (2000) named the promoter P2. In the present study, the same P2 promoter was used for constructing the recombinant baculovirus.…”

Genomics, Molecular Epidemiology and Diagnostics of Infectious hypodermal and hematopoietic necrosis virus

“…Based on physicochemical and ultrastructural properties of the virion and genomic organization, IHHNV is taxonomically placed under the Parvoviridae family [9,55,74]. These are small icosahedral, nonenveloped viral particles 20-22 nm in diameter containing a single-stranded, linear DNA of approximately 3.9 kb [44,69].…”

“…AF218266) and Mexico [74]. Nucleotide sequence analysis of the Indian IHHNV genome reveals three major coding domains: a left ORF (NS1) of 2,001 bp, a mid ORF (NS2) of 1,092 bp and a right ORF (VP) of 990 bp (Fig.…”

“…This ORF encodes a protein of 666 amino acids, with a molecular weight of 75.77 kDa [69]. The ORF1 protein sequence contains highly conserved replication initiator motifs (rolling-circle replication (RCR) motifs) and NTPbinding and helicase domains (ATPase motifs) common to all parvoviruses which is located between 257 and 315 aa and 480 and 579 aa, respectively [1,10,69,74]. The mid ORF of Indian IHHNV strain consists of 1,092 bp.…”

“…The three putative IHHNV promoters (P2, P11 and P61) are located upstream of the left, middle and right ORFs, respectively [23,24,74]. A recent study in USA maping these promoters [24] demonstrated the P2 promoter transcribes the nonstructural protein 1 gene (left ORF), P11 promotes the expression of nonstructural protein 2 gene (middle ORF) and P61 drives the expression of structural protein gene (right ORF).…”