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Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 847 records · Page 47Linked to original sources
PubMed1985

HLA-Bw54 and glaucomatocyclitic crisis.

Twenty-two Japanese patients with glaucomatocyclitic crisis were typed for HLA-A, HLA-B, and HLA-C antigens to detect the immunogenetic factors in this disease. It was shown that HLA-Bw54 was present in nine (41%) of 22 patients, a significant increase even after correcting the P value for the number of antigens studied. The haplotype frequency of HLA-Bw54-Cw1 showed a significant association, and it was not due to linkage disequilibrium in the Japanese. Our results suggest that immunogenetic factors closely associated with the major histocompatibility complex may play an important role in the pathogenesis of glaucomatocyclitic crisis.

Adolescent↗
PubMed1985

The notion of primordial building blocks in construction of genes and transcriptional and processing errors due to random occurrence of oligonucleotide signal sequences.

Contrary to the currently popular belief, genes (flanking and internal noncoding sequences included) that specify beta-sheet and alpha-helical proteins are not unique sequences, rather they are degenerate repeats of short primordial building block sequences that are 45 to 48 bases long in the case of genes belonging to the beta-2-microglobulin superfamily. Accordingly, a large number of base decamers, nonomers, octamers, heptamers and hexamers recur within every gene. One consequence of the above is the random and inadvertent occurrence within genes of various oligonucleotide signal sequences for initiation and termination of transcription as well as for processing of transcripts by removal of intervening sequences. Inadvertent transcription of nonsense sequences and missplicing of transcripts may increase with age and contribute to the aging process. There is little doubt that the life span, being one of the species' characteristics, is genetically programmed. The question remains, however, as to whether or not such a program is embodied in each and every somatic cell type. If the cessation of cell proliferation is regarded synonymous with senescence, one is placed in the awkward position of having to state that most neurons of the central nervous system enter the state of senescence at the neonatal stage. An alternative to the above is the assumption of central control; e.g., the programmed secretion of an aging peptide hormone by the pituitary. To be sure somatic cells accumulate randomly sustained mutations as do germ cells and whatever other genetic mishaps (e.g., deletions, duplications) that may affect somatic cells also occur in germ cells. Yet, the monophyletic germ line on this earth has persisted for three billion years and has the potential of being immortal. Furthermore there can be no direct cause-and-effect relationship between the process of differentiation and the loss of immortality, for spermatozoa are one of the most, if not the most, differentiated cell types that can be found in the body. Nevertheless, if one's scope is confined to the types of genetic mishaps that may afflict somatic cells in their given life span, the one particular type that has hitherto escaped notice should be considered.

Aging↗
PubMed1985

Cellular oncogenes as the ancestors of endocrine and paracrine growth factors and their evolutionary relic status in vertebrates.

Contrary to the popularly held view, genes that have lost their usefulness to the host organism may continue to encode proteins for 50 million years or longer. Accordingly, precisely regulated expression of genes can not be taken as proof of their indispensability. My view is that multitudes of oncogenes of vertebrates are evolutionary relics harking back to the days of invertebrate ancestors in which embryogenesis was still a cell autonomous process. Parts of certain oncogene coding sequences originated from repeats of base oligomers whose numbers of bases were not multiples of three. Thus, these segments are still endowed with a measure of immortality in that they are impervious to normally very deleterious base substitutions, insertions, and deletions.

Animals↗
PubMed1985

Immunocytochemical study on the cytoplasmic side of cell membranes infected with vesicular stomatitis virus by quick-freezing and deep-etching replica method.

Synthesized N protein of vesicular stomatitis virus (VSV) is associated with replicated viral genomes in the infected cells. The cytoplasmic side of cell membranes was examined by quick-freezing and deep-etching replica method, in order to clarify the localization of VSV genomes. Control or infected monolayer Vero cells were fixed in 2% paraformaldehyde, scraped and centrifuged to make pellets. A drop of the cell pellet was put between two glass coverslips, which were coated with 3-aminopropyl triethoxy silane and glutaraldehyde. The cells were consequently split open and postfixed in the mixture of glutaraldehyde and paraformaldehyde. Some inside-out cell membranes on the coverslips were immunostained with anti-N monoclonal antibody directly coupled to gold particles. Others were immunostained with anti-N monoclonal antibody and rabbit anti-mouse IgG coupled to peroxidase and fixed again in glutaraldehyde. They were incubated in diaminobenzidine and hydrogen peroxide solution for 1 min. All of them were infiltrated with 10% methanol in distilled water and quickly frozen in a mixture of isopentane and propane cooled by liquid nitrogen. Such preparations were deep-etched and shadowed by platinum and carbon. Although many cell organelles were found to be associated with the cytoplasmic side of cell membranes in the normal Vero cells, few cell organelles were attached to it in the infected cells. On the contrary, special strand structures were identified, which could be immunostained with anti-N monoclonal antibody. It is concluded that platinum replicas have sufficient resolution to identify the VSV genomes coated with N protein and that these nucleocapsids can be associated with the cytoplasmic side of cell membranes in the infected cells.

Animals↗
PubMed1985

Quantitative radioautographic study of intracellular localization of calmodulin antagonist, W-7, in Chinese-hamster ovary cells.

The purpose of the present study was to analyse quantitatively the localization of calmodulin antagonist, n-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7) in CHO-Kl cells. The cultured CHO-Kl cells were labelled with 1 (16.7 microM), 2 (33.4 microM), 5 (83.5 microM) and 10 microCi/ml (167 microM) tritiated W-7. Some cells were preincubated in 10, 50 and 100 microM unlabelled W-7 for 30 min and then labelled with 2 or 5 microCi/ml tritiated W-7 for 1 h. The cells were doubly fixed in glutaraldehyde and osmium-tetroxide solution, and embedded in Epon. For light-microscopic radioautography, 2 micron-thick sections were wet mounted with radioautographic emulsion and exposed for 1 month. The radioautograms showed that large numbers of silver grains were mainly localized in the cytoplasm as well as in the nucleus. Quantitative analysis demonstrated that, in both the cytoplasm and nucleus, the number of silver grains was dependent on the concentration of the administered tritiated W-7 and the number was dramatically decreased by the pretreatment of unlabelled W-7. These results show that, in CHO-Kl cells, the W-7 binding sites are saturable. It is concluded that W-7 may get into CHO-Kl cells and be bound to a specific protein that may be calmodulin protein.

Animals↗
PubMed1985

Immunocytochemical localization of vesicular stomatitis virus proteins N and NS with monoclonal antibodies.

The purpose of this paper is to describe the immunocytochemical-localization of N and NS nucleocapsid proteins of vesicular stomatitis virus in the cells throughout the infectious cycle. N protein was detected in the cytoplasm at 2 h after infection and formed small cytoplasmic clusters which progressively increased in size and number. At 5-6 h, it formed large cytoplasmic inclusions. NS protein was detected in the cytoplasm a little later than N protein and showed almost the same immunostaining pattern. However, diffuse background staining of NS protein was identified throughout the cytoplasm by double immunostaining methods. At electron microscopic level, N protein was mostly granular and occasionally organized in strands at 2-3 h. At 5-6 h, numerous immunostained reaction products were organized in strands. The reaction products of NS protein were almost the same as those of N protein with the exception that diffuse background staining was observed. Cos cells, transfected with SV40 vector containing N gene obtained by recombinant DNA technique, showed clusters of N protein, but virtually no strand at electron microscopic levels. The rapid-freezing and deep-etching replica method demonstrated that loosely coiled VSV genome coated with N protein was localized on cytoplasmic sides of cell membranes in the infected cells. These results showed that complete virus genome replication was needed for strand formation of N and NS proteins and suggested that they were bound to VSV genomes in the infected cells.

Animals↗
PubMed1985

Delimitation and properties of DNA sequences required for the regulated expression of human interferon-beta gene.

The human interferon-beta (IFN-beta) gene contains sequences within its 5'-flanking region that mediate the virus-induced activation of mRNA transcription. A series of mutant IFN-beta genes, including the 5' deletion mutants, was constructed and introduced into mouse L929 cells. Expression study of those mutant genes demonstrates that: sequences upstream, but not downstream, of -40 from the cap site are responsible for the viral induction of the gene; that the upstream boundary of the DNA sequences required to support the maximum level of induction lies between -117 and -105 from the cap site; and that this upstream sequence shows a property similar to enhancer elements as it functions in either orientation with a latitude in distance from the cap site. Within this sequence, we note the presence of repetitious hexanucleotides (consensus: A-A-AG-TG-G-A), each of which may play a role in the maximum induction of the IFN-beta gene.

Animals↗
PubMed1985

Antigen-binding specificities of antibodies are primarily determined by seven residues of VH.

Although the antigen-binding pocket of all antibodies consists of VL + VH dimers (where VL and VH represent immunoglobulin light and heavy chain regions, respectively), subgroups of their VH largely determine their antigen-binding specificities. This VH subgroup dependence automatically relegates subsidiary roles to VL as a whole and to the complementarity-determining region 3 (CDR-3) of VH encoded by independent diversity (D) and joining (J) coding segments in determining antigen-binding specificities of individual antibodies. As a sequel to our previous paper, which emphasized the role conserved residues in CDR-1 and CDR-2 of VH play in general shaping of the primordial antigen-binding cavity, here we propose that the three short clusters of amino acid sequences in CDR-1 and CDR-2 that are placed in the immediate vicinity of the tryptophan loop primarily determine subgroup-dependent antigen preference of individual VH, therefore, antibodies. The three clusters are the 31st to 35th positions of CDR-1 and the 50th to 52nd and 58th to 60th positions of CDR-2. Of those, the 32nd, 34th, 51st, and 59th positions tend to be occupied by tyrosine, methionine, isoleucine, and tyrosine, respectively. Nevertheless, free amino acid substitutions at the remaining seven sites can generate 20(7) or 1.28 X 10(9) varieties of amino acid sequence combinations. Some of these astronomically numerous sequence combinations no doubt contribute to the maintenance of the vast repertoire of antigen-combining diversity, which might be as large as 10(7), whereas others serve to vary binding affinities toward the same antigen. Ironically, but not surprisingly, a single nonconservative amino acid substitution at one of these sites often suffices to change the antigen preference of VH from one to another, whereas more substitutions affecting two or more clusters are apparently required to change the binding affinity toward the same antigen. In the case of mouse anti-p-azophenylarsonate antibodies, the principle of VH subgroup dependence is violated, their VH belonging to either subgroup 1 or 3. It appears that the mouse genome lacks anti-p-azophenylarsonate germ line VH, residues of CDR-3 derived from one particular JH coding segment coming to rescue to cope with this unnatural man-made antigen.

Amino Acid Sequence↗