INACTIVATION OF CUCUMBER MOSAIC VIRUS (Q STRAIN) NUCLEOPROTEIN BY PANCREATIC RIBONUCLEASE

Purified cucumber mosaic virus (Q strain; QCMV) looses over 90% of its infectivity when virus in 0.01 M phosphate buffer, pH 7.2, is incubated with 0.01 μg/ml of pancreatic ribonuclease (RNase). Changes in the properties of QCMV suspensions treated with RNase under these conditions were investigated by sucrose density-gradient centrifugation and spectrophotometry. It was shown that 30-50% of the viral ribonucleic acid (RNA) is released from QCMV incubated for 1 hour and that on longer incubation the suspension increases in turbidity, which appears to be caused by precipitation of viral protein. It is concluded that QCMV protein only partially protects the viral RNA from enzymatic degradation. © 1968.