The nucleocapsid gene of infectious hematopoietic necrosis virus, a fish rhabdovirus

The complete nucleotide sequence of the infectious hematopoietic necrosis virus (IHNV) nucleocapsid gene has been determined using cDNA clones of genomic and messenger RNAs. Genomic clones were generated by using random DNA oligomers to prime cDNA synthesis and were mapped to their respective locations on the genome by the use of cDNA probes derived from viral mRNAs. Interesting features of the IHNV nucleocapsid gene sequence elucidated by the sequencing of these clones include short homologies with N genes of other rhabdoviruses at the 5' and 3' nontranslated termini of the mRNA, as well as an exceptionally long 5' noncoding region of the mRNA, suggesting a leader RNA may be coupled to the N mRNA. A comparison of the IHNV N protein coding sequence with other rhabdoviral N genes shows some homologies at the amino acid level which indicates the possible evolutionary relationship of these N proteins. The determination of the nucleotide sequences of IHNV genes and intergenic regions will be useful for studying the mechanisms of rhabdoviral transcription and replication.