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Biomedical subjects

I Ise

Publications and source records attributed to I Ise.

At least 19 recordsLinked to original sources
PubMed1997

Mouse homolog of poliovirus receptor-related gene 2 product, mPRR2, mediates homophilic cell aggregation.

Poliovirus receptor (PVR) is a cell surface glycoprotein that belongs to the immunoglobulin superfamily. Although MPH was initially reported as the mouse homolog of human PVR, recent data strongly suggest that MPH is the mouse homolog of human PRR2, a PVR-related gene 2 product, and not that of human PVR. Thus MPH is renamed mPRR2 in this study. Physiological functions of the PVR-related gene products have not been elucidated, although PVR has been well characterized as the poliovirus receptor. In this study, a possible function of mPRR2 (MPH), which is not a functional receptor for poliovirus, was investigated. Mouse L cells expressing mPRR2 were prepared. Those mouse cells showed a higher activity of cell aggregation than the parental mouse L cells. Enhancement of cell aggregation was also observed for insect Sf9 cells infected with recombinant baculovirus carrying mPRR2 cDNA. On the other hand, L cells expressing human PVR or monkey PVR (AGM alpha1 or AGM alpha2) did not show increased cell aggregation. The cell aggregation activity of L cells expressing mPRR2 was inhibited by the addition of anti-mPRR2 monoclonal antibodies or a soluble mPRR2 molecule produced by the baculovirus expression system. An immunofluorescence study revealed that mPRR2 protein was localized to the cell-cell contact sites between cells expressing mPRR2. A similar localization of mPRR2 was observed for intrinsic mPRR2 molecules of the mouse neuroblastoma cell line NS20Y. The contact site-specific localization of mPRR2 was not observed on the border between mPRR2-expressing and nonexpressing HeLa cells. Furthermore, mPRR2 proteins directly bound to each other in vitro. mPRR2 was detected on various types of cultured cells of mouse origin and in various mouse tissues. These results suggest that mPRR2 is an intercellular adhesion molecule with a homophilic binding manner.

Animals↗
PubMed1994

Amino acid residues on human poliovirus receptor involved in interaction with poliovirus.

We have previously demonstrated that the N-terminal immunoglobulin-like domain (domain 1; 115 amino acids) of human poliovirus receptor (hPVR) is essential for poliovirus binding and infection to cells. To identify amino acids involved in the interaction with poliovirus, we constructed a number of cDNAs encoding mutant hPVRs whose domain 1 was partially derived from mouse PVR (mPVR) homolog, which does not serve as a binding site for poliovirus. Poliovirus binding and infection assays were performed on mouse L cells that express these chimera cDNAs. Anti-hPVR monoclonal antibodies were employed to confirm the presence of mutant PVRs on the surface of mouse cells and to know conformational alteration of these PVRs. A significant decrease in efficiency of both poliovirus binding and infection to the cells was observed when one or a few amino acids of hPVR at Gly73, Ser74, Gln82, Leu99-Glu102, or Gln130-Ser132 were substituted by the corresponding amino acids of mPVR. Similar results were obtained when a 2-amino acid insertion of mPVR, which was missing in hPVR, was introduced at the corresponding site (between Arg98 and Leu99) of hPVR. These amino acids were highly conserved in functional PVRs of primates but not in unfunctional PVRs of rodents. These results indicate that the amino acids identified may have important roles in interaction of PVR with poliovirus that leads to the establishment of the virus infection. In the three-dimensional model of the domain 1 of hPVR, these amino acids are located on one side of the molecule. This suggests that the interaction with poliovirus occurs on this side of the domain 1.

Amino Acid Sequence↗
PubMed1994

Characterization of three different transgenic mouse lines that carry human poliovirus receptor gene--influence of the transgene expression on pathogenesis.

Three transgenic mouse lines, ICR-PVRTg1, ICR-PVRTg5, and ICR-PVRTg21, which are susceptible to poliovirus, have been established by introducing the human gene for poliovirus receptor (PVR) into the genome of mouse strain ICR. Genetic characterizations of the PVR gene were carried out on these mouse lines to define the approximate copy number, insertion site, and expression of the transgene in the central nervous system (CNS). The transgene was integrated in the chromosome 4, 12, and 13 of ICR-PVRTg1, ICR-PVRTg5 and ICR-PVRTg21 mice, respectively, and was stably transmitted to progeny mice. ICR-PVRTg1 appeared to have the most abundant copy numbers of the transgene and showed the highest level of PVR mRNA and membrane associated PVR protein in the CNS among the three mouse lines. Those in ICR-PVRTg21 and ICR-PVRTg5 were at intermediate and lowest levels, respectively. In the CNS, PVR mRNA was detected at high levels only in neurons of the spinal cord and brain stem where poliovirus can replicate, suggesting that the PVR mRNA expression confers cell specificity to poliovirus in the CNS. ICR-PVRTg1 and ICR-PVRTg5 showed the highest and the lowest sensitivity to poliovirus, respectively, whereas ICR-PVRTg21 was in-between. These results may suggest that poliovirus sensitivity of the mice is attributed to relative levels of PVR expression.

Animals↗
PubMed1994

Transgenic mice carrying the human poliovirus receptor: new animal models for study of poliovirus neurovirulence.

Recombinant viruses between the virulent Mahoney and attenuated Sabin 1 strains of poliovirus type 1 were subjected to neurovirulence tests using a transgenic (Tg) mouse line, ICR-PVRTg1, that carried the human poliovirus receptor gene. The Tg mice were inoculated intracerebrally with these recombinant viruses and observed for clinical signs, histopathological lesions, and viral antigens as parameters of neurovirulence of the viruses. These parameters observed in the Tg mice were different for different inoculated viruses. Dose-dependent incidences of paralysis and of death were observed in the Tg mice inoculated with any viruses used. This indicates that values of 50% lethal dose are useful to score a wide range of neurovirulence of poliovirus. The neurovirulence of individual viruses estimated by the Tg mouse model had a strong correlation with those estimated by monkey model. Consequently, the mouse tests identified the neurovirulence determinants on the genome of poliovirus that had been identified by monkey tests. In addition, the mouse tests revealed new neurovirulence determinants, that is, different nucleotides between the two strains at positions 189 and 21 and/or 935 in the 5'-proximal 1,122 nucleotides. The Tg mice used in this study may be suitable for replacing monkeys for investigating poliovirus neurovirulence.

Animals↗
PubMed1993

Poliovirus-sensitive transgenic mice as a new animal model.

Transgenic mice susceptible to poliovirus infection were produced by introducing a human gene encoding cellular receptors for poliovirus into the mouse genome. Expression of receptor mRNAs in tissues of the transgenic mice was analysed using Northern blot hybridization. The results indicate that the human gene is expressed in many tissues of the transgenic mice just as in human tissues, and that the amount of the receptor mRNAs varies from tissue to tissue. The transgenic mice inoculated with poliovirus by any of the routes tested in this study show clinical symptoms similar to those in humans and monkeys, although the sensitivity of the mice depended on the inoculation route. In any route, the virulent Mahoney strain of type 1 poliovirus is much more virulent than the attenuated Sabin 1 strain in the transgenic mice. These observations suggest that the transgenic mice become an excellent new animal model for studying molecular mechanisms of pathogenesis of poliovirus and for assessing oral poliovirus vaccines.

Administration, Oral↗
PubMed1992

A second gene for the African green monkey poliovirus receptor that has no putative N-glycosylation site in the functional N-terminal immunoglobulin-like domain.

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 suggested that duplication of the PVR gene in the monkey genome had occurred after the species differentiation 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 human PVR are dispensable for the virus-receptor interaction.

Amino Acid Sequence↗
PubMed1991

Functional domains of the poliovirus receptor.

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.

Animals↗
PubMed1991

Transgenic mice susceptible to poliovirus.

Poliovirus-sensitive transgenic mice were produced by introducing the human gene encoding cellular receptors for poliovirus into the mouse genome. Expression of the receptor mRNAs in tissues of the transgenic mice was analyzed by using RNA blot hybridization and the polymerase chain reaction. The human gene is expressed in many tissues of the transgenic mice just as in tissues of humans. The transgenic mice are susceptible to all three poliovirus serotypes, and the mice inoculated with poliovirus show clinical symptoms similar to those observed in humans and monkeys. Rabbit antipoliovirus serum detects the antigens mainly in motor neurons in the anterior horn of the spinal cord and in nerve cells in the medulla oblongata and pons of the paralyzed transgenic mice. Therefore, cell types sensitive to poliovirus in the central nervous system of the transgenic mice appear to be identical to those of humans and monkeys. Furthermore, many more doses of oral poliovirus vaccine strains than of the virulent strains are required to cause paralysis in the transgenic mice. This may reflect the observation that the virulent strain multiplies more efficiently in the central nervous system than the attenuated strain. Thus, the transgenic mice may become an excellent new animal model to study molecular mechanisms of pathogenesis of poliovirus and to assess oral poliovirus vaccines.

Animals↗
PubMed1990

The poliovirus receptor protein is produced both as membrane-bound and secreted forms.

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 approximately 20 kb 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 beta, PVR gamma and PVR delta. The predicted amino acid sequences indicate that PVR alpha and PVR delta, corresponding to the 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 beta was not detected on the surface of the mouse cell transformants but was detected in the culture fluid by an immunological method using a monoclonal antibody against poliovirus receptor. Three types of splicing products for PVR alpha, PVR beta and PVR gamma 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 delta. In situ hybridization using a cDNA fragment as a probe demonstrated that the PVR gene is located at the band q13.1----13.2 of human chromosome 19.

Amino Acid Sequence↗
PubMed1987

Effect of iodoacetic acid upon cochlear potentials.

Lotz et al. reported that perilymphatic application of 5 X 10(-3) M iodoacetic acid (IAA) in the guinea pig does not influence the first-order cochlear microphonics (CM1) under aerobic conditions. However, in ischemia the rate of decline of the second-order microphonics (CM II, also called postmortem CM) was significantly increased by IAA. The authors concluded that glycolysis plays no role in maintaining the CMI, but that it is responsible for supporting the CMII. In carefully controlled experiments we found that in the respiring guinea pig, perilymphatic application of 5 X 10(-3) M IAA produced a rapid and pronounced effect upon both the endolymphatic potential and the CM. In particular, the CM dropped to less than 0.5% of its initial level within 40 min, due to IAA, whereas it took 120 min to drop to the same level in total ischemia (without IAA). We therefore reject the above-mentioned proposition that IAA is ineffective upon cochlear potentials under aerobic conditions; moreover, we find that even under aerobic conditions, the CM drops well below the usual CM II level substantially faster than under anaerobic conditions (without IAA). Other important findings, including an anoxia-sensitive negative component of the endolymphatic potential due to severe intoxication with IAA, and the effects of pretreatment of the organ of Corti with low concentrations of IAA upon the CM II are discussed.

Aerobiosis↗
PubMed1986

Small and large forms of hepatitis B e antigen in the serum: determination by two-site sandwich radioimmunoassay with monoclonal antibodies.

Serum samples containing hepatitis B e antigen (HBeAg) were subjected to electrophoresis in agarose, and fast-migrating 'small' HBeAg and slow-migrating 'large' IgG-associated HBeAg were pooled separately. HBeAg of each category was determined by a two-site radioimmunoassay that sandwiched HBeAg between monoclonal antibody (anti-HBe) against one epitope of HBeAg, fixed on a solid support, and anti-HBe against another epitope, labelled with radioiodine. Eighteen sera in which small HBeAg dominated revealed activities of hepatitis B surface antigen-associated DNA polymerase significantly higher than 14 sera in which large HBeAg dominated (logarithm of ct/min, mean +/- s.e. 3.36 +/- 0.08 versus 2.14 +/- 0.11, P less than 0.01). Shift from small HBeAg to large HBeAg was observed, along with the disappearance of DNA polymerase, in the serum from two carriers who seroconverted to anti-HBe.

Antibodies, Monoclonal↗
PubMed1982

Maternofetal transmission of IgG-bound hepatitis B e antigen.

Utilizing a highly sensitive radioimmunoassay, hepatitis B e antigen (HBeAg) was detected in the cord serum of eight out of nine babies born to mothers who carried hepatitis B surface antigen together with HBeAg. The titer of HBeAg in the cord serum was much lower than that in the corresponding maternal serum, and escaped the detection by the conventional micro-Ouchterlony immunodiffusion. HBeAg in maternal and cord sera was fractionated into free and IgG-bound moieties by salt precipitation, and their proportion was compared in four pairs. In every pair tested, both free and IgG-bound HBeAg were found in the maternal serum, but only IgG-bound HBeAg was detected in the corresponding cord serum. Based on these results, IgG-bound HBeAg can be transmitted through the placenta, but free HBeAg may barely pass the placenta despite its much smaller size.

Adult↗
PubMed1980

Bone destruction due to the rupture of a cholesteatoma sac: a pathogenesis of bone destruction in aural-cholesteatoma.

Severe bone destruction in a cholesteatoma is one of the characteristic clinical features. To clarify the mechanism of bone destruction in cholesteatoma, the matrix of cholesteatoma and the attached bone, obtained during middle ear surgery, was observed by light microscope. Rupture of the epithelial lining in a cholesteatoma and the escaping contents (keratin), which gave rise to intense characteristic granulations in subepithelial tissue, were found. Furthermore bone destruction was always found at the site of subepithelial tissue of cholesteatoma. From these facts, the escape of contents from the sac of cholesteatoma into the subepithelial layer is considered to be an important factor in the mechanism of bone destruction.

Bone Resorption↗