Full Length cDNA Cloning and Bioinformatics Analysis of Acute Viral Necrosis Virus IAP-86 Gene From Anadara uropygimelana

Abstract:

Acute viral necrosis virus (AVNV) was reported as the causative agent for summer mass mortality of adult Zhikong scallop (Chlamys farreri) that has been widely cultured along northern China coast. To understand the pathogenesis and the function of IAP-86, a strain of acute viral necrosis virus (AVNV) was isolated from Anadara uropygimelana. RNA was extracted from the mantle of moribund A. uropygimelana that was infected with AVNV, and cDNA was obtained by reverse transcription. Two pairs of nested reverse primer were designed according to the ORF86 sequence of AVNV complete genome sequence that registered in NCBI. The non-coding region of 5' and 3' end of the ORF86 were amplified using the designed primers by rapid amplification of cDNA ends (RACE) technique, and the full-length cDNA sequences were spliced. Blast sequence alignment illustrated that this gene has 100% homology with oyster herpetovirus and 99% with the AVNV. Moreover, overlapping genes were found in the cDNA sequence. Bioinformatics analysis indicated that the protein contains neither a signal peptide nor a transmembrane region. The maximum hydrophobic index was 1.800 and the minimum hydrophobic index was 3.456. There are eight potential phosphorylation sites (including five serine sites, two tyrosine sites and one threonine site), a potential O-glycosylation site, but no potential N-glycosylation site. The epitope were mainly located on the amino acids of 811, 1416, 2839, 7576, 8895, 97100 and 147158. Results suggest that the virus may be a strain of oyster herpetovirus, and gene overlapping may play an important role in the virus evolution.