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H Ariga

Publications and source records attributed to H Ariga.

At least 73 records · Page 4Linked to original sources
PubMed1996

Cloning and characterization of the genomic DNA of the human MSSP genes.

MSSP proteins have been identified by their binding to an upstream element of c-myc. Independently, two different approaches yielded two cDNA clones highly homologous to the MSSP cDNAs, suggesting an involvement of MSSP in the regulation of the cell cycle (scr2) and in the repression of HIV-1 and ILR2 alpha-promoter transcription (human YC1). Screening human genomic libraries, we have isolated clones belonging to two different gene loci. Whereas the human MSSP gene 1 turned out to be intronless, the organization of the coding sequence within gene 2 is more complex. It spans more than 60 kb and contains 16 exons (including two alternative first exons), ranging from 48 to 287 bp, respectively. The intron sizes vary from 0.1 to more than 13 kb. Gene 1 has been completely sequenced. A deletion series of its upstream region was conjugated to the luciferase gene, but the transfection of the constructs did not display any promoter activity. Moreover, compared with gene 2 and the cDNA sequences known so far, about 20 point mutations as well as flanking direct repeats have been detected in the MSSP gene 1, showing that it possesses all the characteristics of processed retropseudogenes. Sequence analysis of a 1.7 kb fragment of the 5' flanking region of the MSSP gene 2 revealed that the promoter of gene 2 lacks consensus sequences for TATA and CCAAT boxes, is GC-rich, and contains numerous potential transcription factor binding elements including an Sp1 binding site. DNase I footprinting experiments showed that the putative Sp1 site was bound by proteins. The results of primer extension and S1 mapping analyses suggested the transcription of the gene starts at multiple positions upstream from the initiator methionine codon. Luciferase assays employing progressive deletions of the 1.7 kb promoter region allowed us to define the minimal promoter region of 428 bp (-488/+) and revealed a complex pattern of the transcriptional regulation the human MSSP gene 2. Furthermore, it can be concluded that the MSSP gene 2 encodes both MSSP-1 and MSSP-2, and moreover scr2 and human YC1.

Amino Acid Sequence↗
PubMed1996

Localization, expression, and the role in fertilization of spermosin, an ascidian sperm trypsin-like protease.

In order to elucidate the role of spermosin (a novel sperm trypsin-like protease) in ascidian fertilization, we developed an antibody against the ascidian spermosin: the antibody appears specific to the spermosin but not to the acrosin. By Western blot analysis, spermosin was found to be expressed just before and during the spawning season. Immunocytochemical studies have shown that spermosin is localized on the sperm head. It was found that the spermosin was released from the sperm during the sperm reaction, and the anti-spermosin antibody, but not control antibody, inhibited the fertilization in a concentration-dependent manner. These results indicate that spermosin plays an essential role in ascidian fertilization.

Acrosin↗
PubMed1996

Transcriptional repression activity of N-MYC protein requires phosphorylation by MAP kinase.

The transrepressing function of the N-myc protein is due to the distinct domains located at the N-terminus. In this report we introduced various point mutations around the myc boxes of the N-myc protein to examine whether the phosphorylation of the protein affected its transrepressing function. Serine (Ser) residues located at amino acid numbers 12, 31, 51, and 65 were changed to leucine or arginine, and the expression vectors of the mutant proteins were transfected to HeLa cells together with the luciferase gene linked to the MHC class I gene. Among the mutants, only the N(51)-myc carrying mutation at Ser(51), a target for mitogen-activated protein kinase (MAP kinase), lost the repression activity, while the other mutant proteins preserved it. Formation in vitro of the specific nucleoprotein complexes on the H2TF1/NFkappaB element, a major target for transrepression by N-myc protein, was interfered by the wild-type N-myc protein, but not by the Ser(51)-mutated protein. The results suggest that the phosphorylation of the N-myc protein at Ser(51) by MAP kinase is required for the transcriptional repression activity of the protein.

Amino Acid Sequence↗
PubMed1996

[Analysis of locally controlled esophageal carcinomas treated with radiotherapy].

Of 227 esophageal carcinomas treated with a radiation dose of 60 Gy or more, 100 patients had no tumor or ulceration (with or without stenosis) of the esophagus after irradiation. We analyzed local control factors of these 100 patients to determine the need for further treatment. The cumulative local control rate at five years was 40% in all cases, 37% in 21 cases without any stenosis of the esophagus and 40% in 79 cases with stenosis. The presence of stenosis of the esophagus after irradiation was not a critical factor in predicting final local control. Local recurrence of tumors with findings of Borrmann III or Borrmann IV by the pretreatment esophageal barium study, tumors controlled after a total dose of more than 80 Gy, tumors without low dose rate telecobalt therapy (LDRT; 1 Gy/hour, 5 to 7Gy/day, a total dose of 12 to 15 Gy) as boost therapy, and apparently controlled tumors with a stenotic ratio of 60% or more or with 5 cm or more length of stenosis of the esophagus after irradiation was significantly higher than that of the others (p < 0.05). Multivariate analysis revealed that findings of pretreatment barium study, total dose, with or without LDRT, and length of stenosis of the esophagus after irradiation were significantly important factors in local control. Members of the high risk group of apparently controlled tumors should undertake surgical treatment or further intensive chemotherapy.

Aged↗
PubMed1996

[Apoptosis related gene, Pim-1].

Pim-1, a protooncogene product, induced tumor in the combination with MYC. So far, two reports were published concerning Pim-1 function to apoptosis. One was that Pim-1 inhibit apoptosis in Pim-1 introduced transgenic mouse with a background of lpr/lpr, in which Fas was abrogated. However, the other that Pim-1 induced apoptosis in a transient expression system was also reported. In this communication, we survey the possible functions of Pim-1 in terms of the factor related to apoptosis and carcinogenesis.

Animals↗
PubMed1996

[Leigh syndrome: serial CT and MR imaging findings].

Serial CT and MRI findings in five patients (two boys and three girls) with Leigh syndrome were retrospectively reviewed in a follow-up period lasting from six months to 10 years. The two boys were found to have cytochrome c oxidase deficiency and one of the girls to have mitochondrial DNA mutation, while the remaining two girls had no detectable enzyme deficiency. CT and MRI revealed symmetrical involvement of the brain bilaterally in all cases. The focal lesions were found most frequently in putamina and caudate nuclei (four cases each), followed by thalami (three cases), globi pallidi, and midbrain (two cases each). In addition, diffuse white matter and/or cortical lesions were disclosed in three cases. MRI and CT at an early stage of the disease revealed swollen, symmetrical lesions which showed shrinkage in size accompanied by the adjacent brain atrophy on later images. Some lesions were detected only in the early stage and were not shown in later images. Thus, careful reading of sequential changes appears to be required for accurate diagnosis of Leigh syndrome.

Brain↗
PubMed1995

Involvement of PIM-1 in DNA fragmentation in mouse NS-1-derived cells.

In several cell lines derived from mouse NS-1 myeloma cells, internucleosomal fragmentation of chromosomal DNA, a hallmark of apoptosis, was continuously observed. Approximately 15-20% of the cells died when isolated in a 96-well plate, and the surviving cells contained fragmented DNA ('ladder'). Among a variety of genes so far reported to be related to apoptosis, only Pim-1 was expressed at an elevated level in the NS-1 hybridomas as compared in a control myeloma cell line without 'ladder'. Transfection of a Pim-1 expression vector to a 'ladder'-non-producing myeloma line yielded similar internucleosomal DNA fragmentation. The results hence suggested that Pim-1 activates endonucleases responsible for DNA fragmentation during apoptosis and/or repress DNA repair systems to restore fragmented DNA.

Animals↗
PubMed1995

Diversity of sites for measles virus binding and for inactivation of complement C3b and C4b on membrane cofactor protein CD46.

The complement system membrane cofactor protein (MCP) CD46 serves as a C3b/C4b inactivating factor for the protection of host cells from autologous complement attack and as a receptor for measles virus (MV). MCP consists of four short consensus repeats (SCR) which are the predominant extracellular structural motif. In the present study, we determined which of the four SCR of MCP contribute to its function using Chinese hamster ovary cell clones expressing each SCR deletion mutants. The results were as follows: 1) SCR1 and SCR2 are mainly involved in MV binding and infection; 2) SCR2, SCR3, and SCR4 contribute to protect Chinese hamster ovary cells from human alternative complement pathway-mediated cytolysis; and 3) SCR2 and SCR3 are essential for protection of host cells from the classical complement pathway. These results on cell protective activity of the mutants against the human classical and the alternative complement pathways were compatible with factor I-mediated inactivation profiles of C4b and C3b, respectively, in the fluid-phase assay using solubilized mutants and factor I; the results were mostly consistent with those reported by Adams et al. (Adams, E. M., Brown, M. C., Nunge, M., Krych, M., and Atkinson, J. P. (1991) J. Immunol. 147, 3005-3011). SCR2 and SCR3 were required for C3b and C4b inactivation, and SCR4-deleted MCP showed weak cofactor activity for C4b cleavage but virtually no cofactor activity for C3b cleavage. The functional domains of MCP for the three natural ligands C3b, C4b, and MV, therefore, map to different, although partly overlapping, SCR domains.

Animals↗
PubMed1995

Molecular cloning of the complementary DNA for the mouse pyruvate kinase M-2 gene whose expression is dependent upon cell differentiation.

A cDNA encoding M2-type pyruvate kinase from mouse was cloned and its nucleotide sequence was determined. The cDNA encoded a protein containing 531 amino acids, the nucleotide and amino acid sequences of which were 93.2% and 98.1%, respectively, homologous to those of rat M2 pyruvate kinase. Expression of the pyruvate kinase in mouse embryonal carcinoma P19 cells altered according to differentiation stages; high at undifferentiated and low at differentiated stages.

Amino Acid Sequence↗
PubMed1995

Antagonism of relaxing responses to nitrovasodilators by cyanide in rabbit isolated aortic preparation.

Effect of sodium cyanide on the relaxing response (decrease of intraluminal pressure) to sodium nitroprusside, sodium nitrite, nitric oxide and human atrial natriuretic peptide (HANP) was investigated in isolated rabbit aortic preparations in vitro. Cyanide 1 microM approximately 1 mM produced relaxation in norepinephrine (NE) 1 microM-contracted aortic preparation in a concentration dependent manner. Cyanide 100 microM, which was administered approximately 8 min before NE addition, depressed the relaxing response to nitroprusside 0.1 microM in NE 1 microM-contracted aortic preparation. The relaxing responses to nitric oxide 0.3 and 3.3 microM were slightly, but concentration-dependently depressed by cyanide 1-100 microM, which was administered 6-10 min before nitric oxide addition, in NE 1 microM-contracted aortic preparations. Cyanide 100 microM and 1 mM, which was administered 4-10 min after nitroprusside 0.1 microM, reversed the nitroprusside-induced relaxation in NE 1 microM contracted aortic preparation. Namely, relaxing response of NE-contracted aortic preparation to cyanide was converted into contractile response in the presence of nitroprusside. Similar reversal phenomena of the responses to cyanide 100 microM and 1 mM were also observed in the presence of sodium nitrite 0.1 microM or nitric oxide 3.3 microM, but those were less extent than that of nitroprusside 0.1 microM. On the contrary, the relaxing response to cyanide 100 microM was unaffected by pretreatment with HANP 0.37 nM. These findings may indicate that cyanide inhibits soluble guanylate cyclase activated by nitroprusside, sodium nitrite or nitric oxide through interaction with nitric oxide and heme binding site of the enzyme.

Animals↗
PubMed1994

Molecular cloning of MSSP-2, a c-myc gene single-strand binding protein: characterization of binding specificity and DNA replication activity.

We have previously reported the human cDNA encoding MSSP-1, a sequence-specific double- and single-stranded DNA binding protein [Negishi, Nishita, Saëgusa, Kakizaki, Galli, Kihara, Tamai, Miyajima, Iguchi-Ariga and Ariga (1994) Oncogene, 9, 1133-1143]. MSSP-1 binds to a DNA replication origin/transcriptional enhancer of the human c-myc gene and has turned out to be identical with Scr2, a human protein which complements the defect of cdc2 kinase in S.pombe [Kataoka and Nojima (1994) Nucleic Acid Res., 22, 2687-2693]. We have cloned the cDNA for MSSP-2, another member of the MSSP family of proteins. The MSSP-2 cDNA shares highly homologous sequences with MSSP-1 cDNA, except for the insertion of 48 bp coding 16 amino acids near the C-terminus. Like MSSP-1, MSSP-2 has RNP-1 consensus sequences. The results of the experiments using bacterially expressed MSSP-2, and its deletion mutants, as histidine fusion proteins suggested that the binding specificity of MSSP-2 to double- and single-stranded DNA is the same as that of MSSP-1, and that the RNP consensus sequences are required for the DNA binding of the protein. MSSP-2 stimulated the DNA replication of an SV40-derived plasmid containing the binding sequence for MSSP-1 or -2. MSSP-2 is hence suggested to play an important role in regulation of DNA replication.

Base Sequence↗
PubMed1994

Modulation of complement regulatory function and measles virus receptor function by the serine-threonine-rich domains of membrane cofactor protein (CD46).

Three major membrane cofactor protein (MCP) phenotypes with different serine-threonine (ST)-rich regions, namely STc (L-phenotype), STBC (H or U phenotype) and STABC, and the MCP without the ST domain (delta ST) were expressed in Chinese hamster ovary (CHO) cells by transfecting the respective cDNAs. The expressed molecules migrated with a larger molecular mass on SDS/PAGE than those expected from their amino acid sequences. O-Glycanase digestion showed that this was due to O-linked sugar chains. The apparent sugar contents in each ST segment were compatible with their serine and threonine contents in the ST regions. The functional properties of these phenotypes as inhibitors of human complement (C) and receptors of measles virus (MV) were compared. The classical pathway-dependent CHO cell lysis by human C was more effectively suppressed by the expressed delta ST and STC than by the STABC and STBC phenotypes, although the difference was not so prominent. In contrast, alternative C pathway-dependent CHO-cell lysis was most effectively suppressed by the STABC phenotype and was only slightly blocked by the ST-deleted mutant. MV infection occurred with all of the phenotypes, but the infectious dose required to cause the same level of syncytium formation was 100-times higher in large ST (STABC and STBC) than in small ST (STC and delta ST) phenotypes. Thus, the ST domain serves as a functional modulator in MCP: MCP with a large ST domain having high O-linked sugar contents is favourable to the effective suppression of both the alternative C pathway-mediated cytolysis and MV infection, whereas MCP with a small ST domain is favourable to the suppression of the classical C pathway.

Animals↗
PubMed1994

A major cellular substrate for protein kinases, annexin II, is a DNA-binding protein.

We have screened a human cDNA expression library in lambda gt11 for clones encoding Alu-binding proteins using direct binding of labeled Alu DNA to recombinant phage lysates fixed on a membrane, and isolated a clone 98% identical in sequence to the well-known substrate of protein kinases, annexin II, which was suggested earlier to play a role in transduction of mitogenic signals and DNA replication. A diagnostic property of annexins is their binding to phospholipids in the presence of calcium ions, and we have found that the interaction of proteins of human nuclear extracts with Alu subsequences is suppressed by Ca/phosphatidylserine liposomes, suggesting overlapping of Ca/phospholipid- and DNA-binding domains in annexin II.

Amino Acid Sequence↗
PubMed1994

Identification of novel single-stranded DNA binding proteins recognizing octamer motif.

We have previously identified the region containing transcriptional enhancer in mouse immunoglobulin heavy chain (IgH) gene as an initiation region of DNA replication. The octamer sequence therein has been found to be essential for initiation of DNA replication as well as for transcription. Octamer-binding protein family, including Oct (OTF)-1, 2A, and 2B, bound to the element in double-stranded form. Here we identified in various cells novel proteins which bound to the upper strand of the octamer sequence in the IgH gene. Three proteins of 35, 60, and 125 KDa recognized the sequences. The proteins, which were not recognized by an anti-Oct-1 antibody, may be involved in regulation of the initiation of DNA replication in the IgH gene.

Animals↗
PubMed1994

Expression of a hybrid complement regulatory protein, membrane cofactor protein decay accelerating factor on Chinese hamster ovary. Comparison of its regulatory effect with those of decay accelerating factor and membrane cofactor protein.

C activation on the cell surface is supposedly regulated by membrane cofactor protein (MCP) and decay accelerating factor (DAF). These are complementary in function: MCP acts as a cofactor in factor I-mediated C3b and C4b inactivation, thus preventing the assembly of C3 convertases, whereas DAF accelerates spontaneous decay of the assembled C3 convertase. In this report, a hybrid MCP-DAF was expressed on Chinese hamster ovary cells by transfecting cDNA, and its regulatory activity was compared with those of MCP and DAF transfectants and with a transfectant expressing both MCP and DAF (MCP + DAF). The C3 deposition on sensitized CHO cells through activation of the classical pathway was blocked to a different degree with these transfectants, the order being MCP + DAF > DAF > hybrid MCP-DAF > MCP. Likewise, the C3 deposition via the alternative pathway was blocked efficiently in the order hybrid > MCP + DAF > MCP. The C-mediated cytolysis of CHO cells virtually reflected the degree of C3 fragment deposition. The MCP-DAF transfectant acquired additive protective activity against alternative pathway-mediated C3 deposition and cytolysis but was less potent in circumventing classical pathway attack than cells that expressed DAF alone or DAF + MCP. Hybrid MCP-DAF may be useful for alleviating C-mediated cell damage, especially via the alternative pathway.

Animals↗