CHANGES IN THE NS GENE OF NEUROVIRULENT STRAINS OF INFLUENZA AFFECT SPLICING

The nonstructural (NS) gene has been identified as an accessory factor in determining neurovirulence for influenza A virus. The nucleotide s equence of the NS gene of the neurovirulent variant A/NWS/33 was deter mined and compared with its parent, A/WS/33. Alterations in the mRNA s tructure of the gene were observed that serve to mask the 3' splice si te. Changes in this region were shown to correlate with reduced splici ng of the NS gene in neurovirulent strains.