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Biomedical subjects

O Maruyama

Publications and source records attributed to O Maruyama.

14 recordsLinked to original sources
PubMed1999

Significant differences in the frequency of transcriptional units, types and numbers of repetitive elements, GC content, and the number of CpG islands between a 1010-kb G-band genomic segment on chromosome 9q31.3 and a 1200-kb R-band genomic segment on chromosome 3p21.3.

We determined the nucleotide sequence of the entire 1,010,525-bp insert contained in CEPH YAC clone 867e8. This human genomic segment was derived from chromosome 9q31.3 and corresponds to a G-band region. We compared this segment, in terms of structure, with a previously characterized 1,201,033-bp sequence in CEPH YAC936c1 that had come from a portion of human chromosome 3p21.3 corresponding to an R-band region. The two segments were significantly different with respect to the frequency of transcriptional units, the types and numbers of repetitive elements present, their GC content, and the number of CpG islands. Alu elements, GC content, and CpG islands all showed positive correlations with the abundance of exons, but the distribution of LINE1s did not. These observations might reflect an influence of the first three of these features on the functions or expression of genes in the respective regions. In addition to a novel gene (F36) lying at the centromeric end of the 9q segment, we found a cluster of placenta-specific genes within a small section (about 400 kb) on the telomeric side of YAC867e8. This cluster consisted of four apparently unrelated ESTs and two genes, pregnancy-associated plasma protein-A (PAPP-A) and a novel gene (tentatively named EST-YD1). Our characterization of the two chromosomal regions provided evidence that genes are not evenly distributed throughout the human genome, and that gene richness is correlated with the GC content and with the frequency of either Alu elements or CpG islands.

Alu Elements↗
PubMed1999

A preliminary study of microcapsule suspension for hemolysis evaluation of artificial organs.

A microcapsule suspension, a substitute for animal blood in hemolysis tests, has been developed for evaluation of the absolute hemolytic properties of circulatory artificial organs. The microcapsule suspension was made by dispersing microcapsule slurry into an ethylene glycol sodium chloride solution. The microcapsule slurry was composed of a leuco dye solution and polyurethane membrane made by the reaction between aliphatic poly-isocyanate and polyamine by interfacial polycondensation. The microcapsule was a small particle containing dye inside. The microcapsule suspension was white; the diameter of the microcapsules was from 5 to 100 microns. The specific gravity of the suspension was 1.024, and the membrane was elastic. The fluid showed Newtonian characteristics, different from animal blood, and its viscosity was approximately 5.8 mPa.s. After the microcapsules were destroyed, the leuco dye was extracted with n-hexane from the suspension and was measured by spectroscopy after being colored with acid ethanol. Hemolysis can be regarded as a fatigue fracture of cell membranes rather than a static fracture. The destruction of microcapsules by a Potter type tissue grinder was observed at a low stroke number region and was compared to rat blood. Moreover, hemolysis tests of a commercially available centrifugal blood pump and the prototype of our centrifugal pump for mechanism checks were carried out with bovine blood. The hemolysis level of the prototype pump increased with time while the hemolysis level of the commercial blood pump did not change as much as that of the control when both pumps were tested with the microcapsule suspension. These results are similar to tests utilizing bovine blood. Therefore, hemolysis tests of circulatory artificial organs completed with microcapsule suspension are expected to provide results similar to tests with animal blood.

Animals↗
PubMed1999

A System to Find Genetic Networks Using Weighted Network Model.

We are developing a system which finds a genetic network from data obtained by multiple gene disruptions and overexpressions. We deal with a genetic network as a weighted graph, where each weight represents the strength of activation from a gene to another gene. In this paper, we explain the overview of our system, and our strategy to visualize the weighted network. We also study the computational complexity related to the visualization.

Journal Article↗
PubMed1998

Cloning of TCFL5 encoding a novel human basic helix-loop-helix motif protein that is specifically expressed in primary spermatocytes at the pachytene stage.

We have isolated a novel human gene that is expressed specifically in primary spermatocytes in the testis. The cDNA contains an open reading frame of 1356 bp, encoding a 452-amino-acid protein that includes a basic Helix-Loop-Helix (bHLH) motif. The gene, which was mapped to chromosome region 20q13.3-->qter by fluorescence in situ hybridization, consists of six exons and spans approximately 24 kb of genomic DNA. Immunohistochemical staining located the gene product exclusively in cell nuclei of primary spermatocytes at the pachytene stage, but not in those at the leptonema stage. We named this gene TCFL5 (transcription factor-like 5, basic helix-loop-helix). The cell-type and stage-specific expression of TCFL5 indicates that this protein may function in a crucial role in spermatogenesis as a transcription factor by regulating cell proliferation or differentiation of cells through binding to a specific DNA sequence like other bHLH molecules.

Animals↗
PubMed1998

A System for Identifying Genetic Networks from Gene Expression Patterns Produced by Gene Disruptions and Overexpressions.

A hot research topic in genomics is to analyze the interactions between genes by systematic gene disruptions and gene overexpressions. Based on a boolean network model without time delay, we have been investigating efficient strategies for identifying a genetic network by multiple gene disruptions and overexpressions. This paper first shows the relationship between our boolean network model without time delay and the standard synchronous boolean network model. Then we present a simulator of boolean networks without time delay for multiple gene disruptions and gene overexpressions, which includes a genetic network identifier with a graphic interface that generates instructions for experiments of gene disruptions and overexpressions.

Journal Article↗
PubMed1997

Isolation, mapping and mutation analysis of a human cDNA homologous to the doc-1 gene of the Chinese hamster, a candidate tumor suppressor for oral cancer.

We have isolated a human cDNA encoding a 115-amino-acid polypeptide that revealed 97% identity to a candidate tumor suppressor gene for oral cancer in Mesocricetus auratus (deleted in oral cancer-1; doc-1). It also showed a high degree of homology to a gene induced by TNF-alpha in Mus musculus. To investigate its possible role in esophageal carcinogenesis, we examined genetic alterations and expression levels of the gene in 13 esophageal carcinoma cell lines and 10 primary esophageal carcinomas. No mutation nor reduction of expression was observed in any of the 23 cancer materials examined. These results imply that the human doc-1 homologue is unlikely to play a significant role in esophageal carcinogenesis, although its role in the TNF-alpha signaling pathway remains unclear. We mapped DOC1 to chromosome band 12q24.31 by fluorescence in situ hybridization.

Animals↗
PubMed1996

Amino acids in highly conserved regions near the C-terminus of rat prolactin (PRL) play critical roles similar to those in binding of human GH to the PRL receptor.

The fourth helix (helix 4) in the human growth hormone (hGH) molecule plays a role in binding to the GH receptor as well as the PRL receptor through topologically different amino acids. This study investigated the function of amino acids in the predicted helix 4 of rat prolactin (rPRL) using site-directed mutagenesis. Twenty mutants for 7 amino acid residues were expressed in COS-1 cells and their receptor binding and Nb2 proliferation activities were assayed. It was found that R174 (R at residue number 174), K179, and D181 are indispensable for PRL function, while D176, S177 and C189 are important to some extent. When these results were compared with those reported for binding of hGH to its receptors, the binding of PRL to the PRL receptor was shown to involve amino acids topologically similar to those in the binding of hGH to the PRL receptor, rather than those in the binding of hGH to the GH receptor.

Amino Acid Sequence↗
PubMed1994

Amino acids in the amino terminal region of the rat prolactin contribute to PRL-receptor binding and NB2 cell proliferation activity.

To elucidate the structure-function relationship of rat prolactin, seven conserved or semi-conserved amino acids in the amino terminal region were investigated by site-directed mutagenesis. The antigenicity and electrophoretic mobility, as well as receptor binding and Nb2 cell proliferation in various mutants were assayed. Mutants with the cysteine at position 9 replaced with glycine (C9G), as well as R19G, S24A, Y26S, Y42F and Y42S, decreased the activities of receptor binding and Nb2 cell proliferation. A mutation of residue at 42 resulted in a loss of most of the activities. A mutation of residue at 39 (D39V and D39G) increased both receptor binding and cell proliferation activities. Thus, this study demonstrated that the seven amino acids in the amino terminal region contribute to the biological function of rat prolactin and that tyrosine at 42 is especially important.

Amino Acid Sequence↗
PubMed1993

Molecular cloning of cDNAs encoding two types of gonadotrophin alpha subunit from the masu salmon, Oncorhynchus masou: construction of specific oligonucleotides for the alpha 1 and alpha 2 subunits.

Two types of cDNA (GTH alpha 1 and -alpha 2) encoding the alpha subunits of masu salmon (Oncorhynchus masou) gonadotrophin were cloned by the reverse transcription-polymerase chain reaction for pituitary mRNAs. The nucleotide sequences showed that the GTH alpha 1 cDNA was 380 bp long, encoding 119 amino acids, and that GTH alpha 2 cDNA was 365 bp long, encoding 114 amino acids. The masu salmon alpha subunit types had a few differences between the sequences, with homologies of 80% (nucleotide sequence) and 72% (amino acid sequence). The structural difference between the alpha 1 and alpha 2 subunits was predicted using hydropathic analysis. The evolutionary interval between masu and chum salmon was estimated to be 4.0 and 2.3 million years by comparing their GTH alpha 1 and -alpha 2 subunits respectively. These time values are roughly consistent with the evolutionary time interval (3.0 million years) estimated from fossil records and an isozyme study. Specific synthetic oligonucleotide probes were constructed and used for genomic Southern blot analyses. The restriction fragment sizes of the GTH alpha 1 and -alpha 2 genes were similar, and when their patterns were compared with those from four other teleosts, each species showed a different pattern from the others, but no difference between their respective alpha 1 and alpha 2 genes. Therefore, the structural features of the GTH alpha 1 and -alpha 2 genes may have diverged in a similar manner in these five teleosts.

Amino Acid Sequence↗
PubMed1993

Molecular cloning of cDNAs encoding two gonadotrophin beta subunits (GTH-I beta and -II beta) from the masu salmon, Oncorhynchus masou: rapid divergence of the GTH-I beta gene.

Two types of cDNA (GTH-I beta and -II beta) encoding the beta subunit of masu salmon (Oncorhynchus masou) gonadotrophin were cloned using the reverse transcription-polymerase chain reaction for pituitary mRNAs. The nucleotide sequence of GTH-I beta cDNA was 469 bp long, encoding 137 amino acids, and GTH-II beta cDNA was 476 bp long, encoding 142 amino acids. These two masu salmon beta subunit types showed low homologies of 52% (nucleotide sequence) and 33% (amino acid sequence). The evolutionary interval between masu and chum salmon was estimated to be 5.65 and 1.43 million years by comparing GTH-I beta and GTH-II beta respectively. These time values are markedly inconsistent with the evolutionary time (3.0 million years) estimated from fossil records and an isozyme study. Southern blot analyses showed that the I beta gene restriction fragment lengths differed among five teleosts, whereas, with one exception, the II beta gene showed well conserved patterns. Therefore, the GTH-I beta gene may have diverged at a faster rate than the GTH-II beta gene.

Amino Acid Sequence↗
PubMed1992

Cloning of a bullfrog growth hormone cDNA: expression of growth hormone mRNA in larval and adult bullfrog pituitaries.

A GH cDNA was specifically amplified from cDNAs constructed from total RNA of bullfrog (Rana catesbeiana) adenohypophyses employing the DNA polymerase chain reaction. Sequencing analysis revealed that the cDNA clone thus obtained was 654 bp in length, and included an open reading frame encoding the entire sequence of mature GH, with its signal peptide. Slight discrepancies were noted between the deduced amino acid sequence and that determined by direct protein sequencing of purified bullfrog GH or that deduced from the nucleotide sequence reported previously. The length of the bullfrog GH mRNA was estimated to be about 1.2 kb by Northern blot analysis. Homologies of nucleotide and amino acid sequences between GH and prolactin of bullfrog origin were 48% and 26% respectively. Using the cDNA as a probe, the content of GH mRNA in the pituitary of larval and adult bullfrogs was measured. GH mRNA levels were relatively low at the preclimax stage, and rose markedly during climax. In juvenile frogs, GH mRNA levels in the pituitary were extremely high and declined towards adulthood. This finding suggests that the increase in plasma and pituitary GH levels reported previously accompanies the increase in GH synthesis.

Amino Acid Sequence↗