THE NV GENES OF FISH RHABDOVIRUSES - DEVELOPMENT OF RNASE PROTECTION ASSAYS FOR RAPID ASSESSMENT OF GENETIC-VARIATION

The genomic RNA of the fish rhabdovirus infectious hematopoietic necro sis virus (IHNV) contains a small NY gene which is not present in any other rhabdoviruses characterized to date. We have constructed a plasm id which carries a full length cDNA copy of the IHNV NV gene between 2 RNA polymerase promoters such that plus-sense and minus-sense RNA tra nscripts of the IHNV NV gene can be synthesized. These were used to de velop an RNase protection assay which was capable of detecting as litt le as 1-5 ng of NV mRNA or genormic RNA. RNA from tissue culture cells infected with 3 different strains of IHNV showed distinct, diagnostic cleavage patterns reflecting sequence variation in their NV genes.