Nuclear localization of poliovirus capsid polypeptide VP1 expressed as a fusion protein with SV40-VP1.
The poliovirus cDNA fragment coding for capsid polypeptide VP1 was inserted between the EcoRI and BamHI sites of SV40 DNA, generating a chimaeric gene in which the sequence of the 302 amino acids (aa) of poliovirus capsid polypeptide VP1 was placed downstream from that of the 94 N-terminal aa of SV40 capsid polypeptide VP1. The resulting defective, hybrid virus, SV40-delta 1 polio, was propagated in CV1 cells using an early SV40 mutant, am404, as a helper. Cells doubly infected by SV40-delta 1 polio and am404 expressed a 50-kDal fusion protein which was specifically immunoprecipitated by polyclonal and/or monoclonal antibodies raised against poliovirus capsids or against poliovirus polypeptide VP1. Examination of the infected cells by immunofluorescence after staining with anti-poliovirus VP1 immune sera revealed that the fusion protein was mostly located in the intra- and perinuclear space of the cells, in contrast to the exclusively intracytoplasmic location of genuine poliovirus VP1 polypeptide that was observed in poliovirus-infected cells. This suggests that the N-terminal part of the SV40-VP1 polypeptide could contain an important sequence element acting as a migration signal for the transport of proteins from the cytoplasm to the nucleus.
D000818:Animals; D002213:Capsid / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004274:DNA, Recombinant; D005814:Genes, Viral; D000882:Haplorhini; D017955:Poliovirus / Q000235:genetics*; D011401:Promoter Regions, Genetic; D013539:Simian virus 40 / Q000235:genetics*; D014158:Transcription, Genetic
D004274:DNA, Recombinant