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Báo cáo khoa học: "Molecular characterization of the virulent infectious hematopoietic necrosis virus (IHNV) strain 220-90"

Molecular characterization of the virulent infectious hematopoietic necrosis virus (IHNV) strain 220-90 | Ammayappan et al. Virology Journal 2010 7 10 http www.virologyj.eom content 7 1 10 VIROLOGY JOURNAL RESEARCH Open Access Molecular characterization of the virulent infectious hematopoietic necrosis virus IHNV strain 220-90 Arun Ammayappan1 2 Scott E LaPatra3 Vikram N Vakharia1 Abstract Background Infectious hematopoietic necrosis virus IHNV is the type species of the genus Novirhabdovirus within the family Rhabdoviridae infecting several species of wild and hatchery reared salmonids. Similar to other rhabdoviruses IHNV has a linear single-stranded negative-sense RNA genome of approximately 11 000 nucleotides. The IHNV genome encodes six genes the nucleocapsid phosphoprotein matrix protein glycoprotein non-virion protein and polymerase protein genes respectively. This study describes molecular characterization of the virulent IHNV strain 220-90 belonging to the M genogroup and its phylogenetic relationships with available sequences of IHNV isolates worldwide. Results The complete genomic sequence of IHNV strain 220-90 was determined from the DNA of six overlapping clones obtained by RT-PCR amplification of genomic RNA. The complete genome sequence of 220-90 comprises 11 133 nucleotides GenBank GQ413939 with the gene order of 3 -N-P-M-G-NV-L-5 . These genes are separated by conserved gene junctions with di-nucleotide gene spacers. An additional uracil nucleotide was found at the end of the 5 -trailer region which was not reported before in other IHNV strains. The first 15 of the 16 nucleotides at the 3 - and 5 -termini of the genome are complementary and the first 4 nucleotides at 3 -ends of the IHNV are identical to other novirhadoviruses. Sequence homology and phylogenetic analysis of the glycoprotein genes show that 220-90 strain is 97 identical to most of the IHNV strains. Comparison of the virulent 220-90 genomic sequences with less virulent WRAC isolate shows more than 300 nucleotides changes in the genome which doesn t allow one to speculate putative residues