Identification of specific fragments containing the 5′end of poliovirus RNA after ribonuclease III digestion

摘要

The small protein (VPg) covalently linked to the 5′end of poliovirus Type 1 (PV-1) RNA has been labeledinvitrowith125I using the Bolton and Hunter reagent. The RNA is not degraded under the conditions used and nearly all the label enters VPg and not the polynucleotide chain. When this125I-labelled RNA is cleaved with RNase III at low monovalent salt concentrations one major125I-labelled fragment, approximately 100 nucleotides long, is produced. The corresponding fragment from similar digests of32P-labelled RNA has also been identified. The32P-labelled fragment changes electrophoretic mobility after protease treatment indicating that it contains VPg. Furthermore, the RNase T1 oligonucleotide known to be at the 5′terminus of poliovirus RNA is found in T1 digests of the purified fragment. These results confirm that the fragment is derived from the 5′end of the RNA. This fragment will be useful in studies concerning the initiation of protein synthesis during poliovirus infe