The P2 and P3 regions of the poliovirus genome are preferentially translated at alkaline pH in infected HeLa cells.
HeLa cells infected with poliovirus exclusively synthesized proteins coded by the P2 and P3 regions of the viral genome when they were placed in an alkaline medium lacking sodium ions. The amount of viral protein synthesized was augmented by increasing the concentration of KCl. Also in the presence of KCl, the cells continued synthesizing this altered pattern of proteins for longer times. This effect occurred in the presence of guanidine, it was reversible, and the normal pattern of poliovirus proteins reappeared when control medium was added, even when guanidine was present. These findings suggest that truncated viral RNA is not made under these conditions. Pactamycin and sodium fluoride, two known inhibitors of the initiation of translation, blocked protein synthesis in cells placed in alkaline medium, indicating the possibility that initiation at internal sites of the viral mRNA may take place under these conditions. Finally, the proteins synthesized were analysed by two-dimensional gel electrophoresis. The proteins migrated as authentic viral proteins indicating that if internal initiation takes place, at least some of these initiation events occur in phase with the initiation codon present in the poliovirus genome.
Castrillo
J L
JL
Centro de Biología Molecular (CSIC-UAM), Universidad Autónoma, Madrid, Spain.
Urzainqui
A
A
Carrasco
L
L
D003513:Cycloheximide / Q000494:pharmacology; D005814:Genes, Viral; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010142:Pactamycin / Q000494:pharmacology; D017955:Poliovirus / Q000235:genetics*; D012969:Sodium Fluoride / Q000494:pharmacology; D014764:Viral Proteins / Q000096:biosynthesis
D006146:Guanidines; D014764:Viral Proteins; D010142:Pactamycin; D012969:Sodium Fluoride; D003513:Cycloheximide; D019791:Guanidine