Infection of HeLa cells with poliovirus results in modification of a complex that binds to the rRNA promoter.
In HeLa cells, RNA polymerase I (Pol I)-mediated transcription is severely inhibited soon after infection with poliovirus. We have developed a gel retardation assay to analyze DNA-protein complexes formed at the Pol I promoter. We show here that two complexes (A and C) formed by nuclear extracts from uninfected cells disappear after infection of cells with poliovirus. In contrast, a new, rapidly migrating complex (D) is formed in virus-infected cell extract. This change in the mobility of gel-retarded complexes correlates well with the kinetics of inhibition of rRNA transcription in virus-infected cells. Incubation of nuclear extracts from mock-infected cells with bacterially expressed, purified poliovirus protease 3C results in the disappearance of complexes A and C with concomitant generation of complex D. A partially purified transcription factor fraction derived from uninfected cells that contains complex A is able to restore Pol I transcription when added to virus-infected cell extracts, suggesting that this complex plays an important role in Pol I transcription. These results suggest that poliovirus proteinase 3C may have an important role in the shutoff of Pol I transcription in cells infected with poliovirus.
Rubinstein
S J
SJ
Department of Microbiology and Immunology, UCLA School of Medicine.
Hammerle
T
T
Wimmer
E
E
Dasgupta
A
A
D000086042:3C Viral Proteases; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006790:Host-Parasite Interactions; D006801:Humans; D008969:Molecular Sequence Data; D011051:Poliomyelitis / Q000235:genetics*; D017955:Poliovirus / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012318:RNA Polymerase I / Q000096:biosynthesis; D012335:RNA, Ribosomal / Q000235:genetics*; D013347:Subcellular Fractions / Q000378:metabolism; D014764:Viral Proteins
D004268:DNA-Binding Proteins; D012335:RNA, Ribosomal; D014764:Viral Proteins; D003513:Cycloheximide; D012318:RNA Polymerase I; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases