References

Notes: Department of Microbiology, Tokyo Metropolitan Institute of Medical Science, Japan 0027-8424 ENGLISH UNITED-STATES A number of mutant cDNAs of the human poliovirus receptor were constructed to identify essential regions of the molecule as the receptor. All mutant cDNAs carrying the sequence coding for the entire N-terminal immunoglobulin-like domain (domain I) confer permissiveness for poliovirus to mouse L cells, but a mutant cDNA lacking the sequence for domain I does not. The transformants permissive for poliovirus were able to bind the virus and were also recognized by monoclonal antibody D171, which competes with poliovirus for the cellular receptor. These results strongly suggest that the poliovirus binding site resides in domain I of the receptor. Mutant cDNAs for the sequence encoding the intracellular peptide were also constructed and expressed in mouse L cells. Susceptibility of these cells to poliovirus revealed that the entire putative cytoplasmic domain is not essential for virus infection. Thus, the cytoplasmic domain of the molecule appears not to play a role in the penetration of poliovirus JOURNAL-ARTICLE 0; 9007-49-2 91239515 9108
Reference ID: 4831

Notes: Department of Microbiology, University of Tokyo, Japan 0022-538X ENGLISH UNITED-STATES Mouse cells expressing the human poliovirus receptor (PVR-mouse cells) as well as human HeLa cells are susceptible to poliovirus type 1 Mahoney strains and produce a large amount of progeny virus at 37 degrees C. However, the virus yield is markedly reduced at 40 degrees C in PVR-mouse cells but not in HeLa cells. The reduction in virus yield at 40 degrees C appears to be due to a defective initiation process in positive-strand RNA synthesis (K. Shiroki, H. Kato, S. Koike, T. Odaka, and A. Nomoto, J. Virol. 67:3989-3996, 1993). To gain insight into the molecular mechanisms involved in this detective process, naturally occurring heat-resistant (Hr)-mutants which show normal growth ability in PVR-mouse cells even at 40 degrees C were isolated from a virus stock of the Mahoney strain and their mutation sites that affect the phenotype were identified. The key mutation was a change from adenine (A) to guanine (G) at nucleotide position (nt) 133 within the 5' noncoding region of the RNA. This mutation also gave an Hr phenotype to the viral plus-strand RNA synthesis in PVR-mouse cells. Mutant Mahoney strains with a single point mutation at nt 133 (A to G, C, or T or deletion) were investigated for their ability to grow in PVR-mouse cells at 40 degrees C. Only the mutant carrying G at nt 133 showed an Hr growth phenotype in PVR-mouse cells. These results suggest that a host cellular factor(s) interacts with an RNA segment around nt 133 of the plus-strand RNA or the corresponding region of the minus-strand RNA, contributing to efficiency of plus-strand RNA synthesis JOURNAL-ARTICLE 0; 0; 0 96013778 9602
Reference ID: 4832

Notes: Using cDNA of the human poliovirus receptor (PVR) as a probe, two types of cDNA clones of the monkey homologs were isolated from a cDNA library prepared from an African green monkey kidney cell line. Either type of cDNA clone rendered mouse L cells permissive for poliovirus infection. Homologies of the amino acid sequences deduced from these cDNA sequences with that of human PVR were 90.2 and 86.4%, respectively. These two monkey PVRs were found to be encoded in two different loci of the genome. Evolutionary analysis between humans and monkeys, The NH2-terminal immunoglobulin-like domain, domain 1, of the second monkey PVR, which lacks a putative N-glycosylation site, mediated poliovirus infection. In addition, a human PVR mutant without N-glycosylation sites in domain 1 also promoted viral infection. These results suggest that domain 1 of the monkey receptor also harbors the binding site for poliovirus and that sugar moieties possibly attached to this domain of huma PVR are dispensable for the virus-receptor interaction.
Reference ID: 4833

Notes: Both genomic and complementary DNA clones encoding poliovirus receptors were isolated from genomic and complementary DNA libraries prepared from HeLa S3 cells, respectively. Nucleotide sequence analysis of these cloned DNAs revealed that the poliovirus receptor gene is -20Kb long and contains seven introns in the coding region, and that at least four mRNA isoforms referring to the coding sequence are generated by alternative splicing and appear to encode four different molecules, that is, PVR alpha, PVR behta, PVR ganma and PVR delta. The predicted amino acid sequences indicate that PVR alpha and PVR ganma corresponding tothe previously described cDNA clones H20A and H20B, respectively, are integral membrane proteins while the other two molecules described here for the first time lack a putative transmembrane domain. Mouse cell transformants carrying PVR alpha were permissive for poliovirus infection, but those carrying PVR beta were hardly permissive. In contrast to PVR alpha, PVR behta was not detected on the surface of the mouse cell transformatints but was detected in the culture fluid by against poliovirus receptor. Three types of splicing products for PVR alpha, PVR behta and PVR gannma were detected by polymerase chain reactions using appropriate primers in poly(A)+ RNAs of the brain, leukocyte, liver, lung and placenta of humans: the choice of primers used did not permit detection of PVR gannma. In situ hybridization using a cDNA fragment as a probe demonstrated that the PVR gene is located at the band q13.1 - q13.2 of human chromosome 19.
Reference ID: 4834

Notes: Two cell lines, TgSVA and TgSVB, were established from the kidneys of transgenic mice carrying the human gene encoding poliovirus receptor. The cells were highly susceptible to poliovirus infection, and a large amount of infectious particles was produced in the infected cells at 37 C. However, the virus yield was greatly reduced at 40 C. This phenomenon was common to all mouse cells tested. To identify the temperature-sensitive step(s) of the virus infection cycle, different steps of the infection cycle were examined for temperature sensitiveity. The results strongly suggestd that the growth restiction observed at 40 C was due to reduced effeciency of the synthesis of positive-strand RNA. Virus-specific RNA synthesis in crude replication complexes was not affected by the nonpermissive temperature of 40 C. In vitro uridylylation of VPg seemed to be temperature sensitive only after prolonged incubation at 40 C. These results indicate that a specific host factor(s) is involved in the evvidient initiation process of positive-strand RNA synthesis of poliovirus and that the host factor(s) is temperature sensitive in TgSVA and TgSVB cells.
Reference ID: 4835