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H Mitsui

Publications and source records attributed to H Mitsui.

At least 37 records · Page 2Linked to original sources
PubMed1999

Characterization of katD, a kinesin-like protein gene specifically expressed in floral tissues of Arabidopsis thaliana.

Kinesin and kinesin-like proteins (KLPs) are microtubule-based motor proteins that play important roles in organelle transport. Based on the homology to these proteins, a katD cDNA has now been isolated from a library prepared from flowers of Arabidopsis thaliana ecotype Columbia. Sequence analysis of the katD cDNA revealed an open reading frame of 2691bp [corrected], encoding a protein of 987 amino acids. Comparison of the nucleotide sequences of katD genomic and cDNA clones revealed the presence of 18 introns, 17 of which conform to the GU-AG rule. The central region of the KatD polypeptide exhibits substantial amino acid sequence homology to the motor domain of kinesin heavy chains, although the motor domain of KatD appears to be phylogenetically distant from those of other KLPs in plants. The amino-terminal region of KatD shares marked sequence similarity with the calponin homology domain, whereas the approximately 240-residue carboxyl-terminal region shows no significant homology to other known proteins. The predicted secondary structure of KatD revealed the lack of an alpha-helical coiled coil structure typical of kinesin heavy chains, suggesting that KatD may function as a monomeric motor. A recombinant truncated KatD protein containing the putative motor domain was shown both to bind to mammalian microtubules in a manner dependent on a non-hydrolyzable ATP analog, and to possess microtubule-dependent ATPase activity. Immunoblot and Northern blot analyses showed that both KatD protein and mRNA are expressed specifically in floral tissues. These results suggest that the structurally distinct KatD protein functions as a floral tissue-specific motor protein.

Adenosine Triphosphatases↗
PubMed1999

Differential regulation of rheumatoid synovial cell interleukin-12 production by tumor necrosis factor alpha and CD40 signals.

OBJECTIVE: To investigate the roles of tumor necrosis factor alpha(TNFalpha) and the CD40-CD154 interaction in interleukin-12 (IL-12) production by rheumatoid synovial cells (SC). METHODS: Levels of IL-12 (p40 and p70) in synovial tissue and culture supernatants of SC from patients with rheumatoid arthritis (RA), osteoarthritis (OA), and ankylosing spondylitis (AS) were assayed by enzyme-linked immunosorbent assay. Effects of anti-CD154 and anti-TNFalpha antibody on spontaneous and lipopolysaccharide (LPS)-stimulated IL-12 production by SC were examined. Effects of immobilized anti-CD3 treatment and depletion of CD4+ T cells on IL-12 production were also tested. CD154 expression by synovial T cells and intracellular IL-12 production during culture were analyzed by flow cytometry. RESULTS: IL-12 p40 and p70 levels in RA synovial tissue and spontaneous IL-12 p40 production by SC from RA patients were significantly higher than the levels in OA and AS patients. Spontaneous IL-12 production by SC from RA patients significantly decreased after depletion of CD4+ T cells from SC or after application of anti-CD154 antibody, but not by treatment with anti-TNFalpha antibody. Anti-CD3 antibody stimulation increased spontaneous IL-12 p40 production and CD154 expression by synovial T cells. The increment of IL-12 p40 production by anti-CD3 was abrogated by anti-CD154 antibody. IL-12 p40 production was also increased by LPS stimulation. LPS-stimulated IL-12 production was inhibited by anti-TNFalpha antibody, but not by T cell depletion and anti-CD154 antibody treatment. The TNFalpha inhibitor rolipram inhibited LPS-stimulated IL-12 p40 production by RA SC more strongly than spontaneous production. TNFalpha restored LPS-stimulated IL-12 production that had been inhibited by rolipram. CONCLUSION: IL-12 production in RA is regulated by 2 different pathways. One pathway is T cell dependent, predominantly through a CD40-CD154 interaction, while the other is T cell independent, mediated through TNFalpha. Inhibition of IL-12 production by interference with CD40-CD154 interaction and TNFalpha production may be a potential therapeutic strategy for treating RA.

Adjuvants, Immunologic↗
PubMed1999

The role of p53 in bleomycin-induced DNA damage in the lung. A comparative study with the small intestine.

To elucidate the role of p53 and apoptosis in the pathogenesis of lung injury, we examined histological changes, expressions of p53 and p21waf1/cip1 (p21), apoptosis, DNA double strand breaks, cell kinetics, and DNA synthesis in C57/BL6 mice (p53+/+) and mice deficient for p53 (p53-/-) at 2 hours to 7 days after a single intravenous administration of bleomycin. We also compared these parameters between the lung cells and small intestinal epithelial cells to explore potential differences in their response to DNA damage. Bleomycin induced p21 expression in a p53-dependent manner in p53+/+ mice but neither p53 nor p21 expression in p53-/- mice. In the lung of both groups of mice, focal inflammation followed by fibrosis was observed, but there was no evidence of apoptosis. Cells with DNA breaks and those undergoing DNA synthesis were unequivocally increased, but the cycling cell fraction remained unchanged, suggesting that the DNA synthesis detected in the lung reflected unscheduled DNA synthesis for repair of damaged DNA. DNA breaks and unscheduled DNA synthesis were prolonged in p53-/- mice compared to p53+/+ mice. By contrast, in the small intestine, marked cell cycle arrest and extensive apoptosis were evoked in the cycling crypt cells of both groups of mice, but these changes were milder and DNA breaks remained detectable for a longer time in p53-/- mice than in p53+/+ mice. Among the resting enterocytes in the villi, apoptosis was observed almost equally in both groups, but repair of DNA breaks was significantly delayed in the p53-/- mice. These observations imply that apoptosis is mediated largely by the p53-dependent pathway in the crypts but exclusively by the p53-independent pathway in the villi, that this pathway is particularly important in DNA repair in the villi, and that despite this difference in the significance of apoptosis, p53 plays an important role in DNA repair in both the crypts and villi. Our results suggest that the lung cells and small intestinal cells respond to the bleomycin treatment in different ways in terms of the induction of apoptosis and that p53 carries out an essential role in the early response to and repair of DNA damage by a non-apoptotic mechanism which appears to be crucial in the noncycling lung cells and enterocytes. Importantly, the p53-p21 pathway and apoptosis are unlikely to be essential for bleomycin-induced tissue injury in the lung.

Animals↗
PubMed1999

IS1631 occurrence in Bradyrhizobium japonicum highly reiterated sequence-possessing strains with high copy numbers of repeated sequences RSalpha and RSbeta.

From Bradyrhizobium japonicum highly reiterated sequence-possessing (HRS) strains indigenous to Niigata and Tokachi in Japan with high copy numbers of the repeated sequences RSalpha and RSbeta (K. Minamisawa, T. Isawa, Y. Nakatsuka, and N. Ichikawa, Appl. Environ. Microbiol. 64:1845-1851, 1998), several insertion sequence (IS)-like elements were isolated by using the formation of DNA duplexes by denaturation and renaturation of total DNA, followed by treatment with S1 nuclease. Most of these sequences showed structural features of bacterial IS elements, terminal inverted repeats, and homology with known IS elements and transposase genes. HRS and non-HRS strains of B. japonicum differed markedly in the profiles obtained after hybridization with all the elements tested. In particular, HRS strains of B. japonicum contained many copies of IS1631, whereas non-HRS strains completely lacked this element. This association remained true even when many field isolates of B. japonicum were examined. Consequently, IS1631 occurrence was well correlated with B. japonicum HRS strains possessing high copy numbers of the repeated sequence RSalpha or RSbeta. DNA sequence analysis indicated that IS1631 is 2,712 bp long. In addition, IS1631 belongs to the IS21 family, as evidenced by its two open reading frames, which encode putative proteins homologous to IstA and IstB of IS21, and its terminal inverted repeat sequences with multiple short repeats.

Amino Acid Sequence↗
PubMed1999

[The removal of renal carcinoma thrombus extending to the right atrium by means of extracorporeal circulation: report of a case].

A case of renal cell carcinoma with a tumor thrombus extending to the right atrium was reported. A 70-year-old woman was admitted with a diagnosis of right renal tumor which had been detected on a routine abdominal ultrasonography. MRI revealed a tumor thrombus extending into the right atrium through the inferior vena cava. A transesophageal echocardiogram confirmed that the tumor extended into the right atrium, and was not adherent to the inferior vena cava and the atrium. Right nephrectomy and removal of the tumor thrombus were performed using extracorporeal circulation. Temporary occlusion of portal venous and hepatic arterial inflow was effective in reducing blood loss. She has been doing well, and there has been no evidence of recurrence during 18 month postoperatively.

Aged↗
PubMed1999

HLA-B27 subtypes and HLA class II alleles in Japanese patients with anterior uveitis.

PURPOSE: Some patients with anterior uveitis (AU) have ankylosing spondylitis (AS) and are HLA-B27 class I-positive. The purpose of this study was to investigate whether there are differences in HLA at the allele level among each group of patients with AU. METHODS: Seventy-three patients with AU were studied. They were classified into three groups: 31 with AS-associated AU, 14 with HLA-B27-associated AU, and 28 with idiopathic AU. Three control groups without AU were used: 138 random subjects, 33 HLA-B27-positive healthy subjects, and 19 HLA-B27-positive patients with AS. DRB1 and DQB1 genotyping was performed using polymerase chain reaction (PCR)-single-strand conformation polymorphism (PCR-SSCP) and PCR-restriction fragment length polymorphism. HLA-B27 subtype was determined by PCR-SSCP. RESULTS: There was no difference in the frequency of any class I antigen except HLA-B27 among the patients studied. The frequencies of HLA-DR12 in AS-associated AU and HLA-DR1 in HLA-B27-associated AU showed an increase. In HLA-B27-associated AU, DRB1*0101 and DQB1*0501 were increased compared with HLA-B27-positive control subjects. When HLA-B27 subtype distribution was compared among the groups, the proportion of B*2704 was significantly lower in HLA-B27-associated AU (P = 0.037), however, such a difference was not present in AS-associated groups. CONCLUSIONS: These results indicated that B*2704 seemed to be less susceptible to AU compared with B*2705 in Japanese subjects. The increase of HLA-DR12 and HLA-DR1 in AU may be caused by linkage disequilibrium with B*2704 and B*2705, respectively.

Adult↗
PubMed1998

Growth-supporting activities of fibronectin on hematopoietic stem/progenitor cells in vitro and in vivo: structural requirement for fibronectin activities of CS1 and cell-binding domains.

Fibronectin (FN) is supposed to play important roles in various aspects of hematopoiesis through binding to very late antigen 4 (VLA4) and VLA5. However, effects of FN on hematopoietic stem cells are largely unknown. In an effort to determine if FN had a growth-supporting activity on hematopoietic stem cells, human CD34(+)/VLA4(bright)/VLA5(dull) hematopoietic stem cells and a murine stem cell factor (SCF)-dependent multipotent cell line, EML-C1, were treated with or without FN in a serum and growth-factor-deprived medium, and then subjected to clonogenic assay in the presence of hematopoietic growth factors. The pretreatment of the CD34(+) cells with FN gave rise to significantly increased numbers of granulocyte-macrophage colony-forming units (CFU-GM), erythroid burst colony-forming units, and mixed erythroid-myeloid colony-forming units. In addition, the numbers of blast colony-forming units and CFU-GM that developed after culture of EML-C1 cells with SCF and the combination of SCF and interleukin-3, respectively, were augmented by the pretreatment with FN. The augmented colony formation by FN was completely abrogated by the addition of CS1 fragment, but not of GRGDSP peptide, suggesting an essential role of FN-VLA4 interaction in the FN effects. Furthermore, the effects of various FN fragments consisting of RGDS-containing cell-binding domain (CBD), heparin-binding domain (HBD), and/or CS1 portion were tested on clonogenic growth of CD34(+) cells. Increased colony formation was induced by CBD-CS1 and CBD-HBD-CS1 fragments, but not with other fragments lacking CBD or CS1 domains, suggesting that both CS1 and CBD of FN were required for the augmentation of clonogenic growth of hematopoietic stem/progenitor cells in vitro. In addition to the in vitro effects, the in vivo administration of CBD-CS1 fragment into mice was found to increase the numbers of hematopoietic progenitor cells in bone marrow and spleen in a dose-dependent manner. Thus, FN may function on hematopoietic stem/progenitor cells as a growth-supporting factor in vitro and in vivo.

Amino Acid Sequence↗
PubMed1998

MICA allele typing of HLA-B27 positive Japanese patients with seronegative spondylarthropathies and healthy individuals: differential linkage disequilibrium with HLA-B27 subtypes.

OBJECTIVE: To examine whether MICA (major histocompatibility complex [MHC] class I-related chain gene A) confers additional susceptibility for seronegative spondylarthropathies in HLA-B27 positive Japanese individuals. METHODS: A polymerase chain reaction-single-strand conformation polymorphism method was developed, and the MICA alleles of 18 Japanese patients with ankylosing spondylitis, 1 patient with Reiter's syndrome, and 17 healthy HLA-B27 positive Japanese subjects were determined. RESULTS: Among 26 individuals with HLA-B*2704 (13 patients and 13 healthy subjects), all except 1 healthy individual were positive for MICA010, whereas all 9 HLA-B*2705 positive subjects (6 patients and 3 healthy subjects) possessed MICA007. One healthy individual with HLA-B*2711 also carried MICA010. CONCLUSION: Strong linkage disequilibrium is present between HLA-B*2704 and MICA010, as well as between HLA-B*2705 and MICA007. Although HLA-B*2704 and B*2705 are highly homologous, each subtype participates in a different MHC haplotype. Direct involvement of MICA polymorphism in the pathogenesis seems to be unlikely; however, such information will provide a useful tool for elucidating the evolutional pathway of HLA-B27 subtypes as well as the contribution of other genes within the MHC region in the pathogenesis of these diseases.

Alleles↗
PubMed1998

Thrombin activates two stress-activated protein kinases, c-Jun N-terminal kinase and p38, in HepG2 cells.

Recently identified c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase are activated by stimuli of various cellular stresses, cytokines, and growth factors. Strong activation of JNK was reported in the regenerating liver, implicating JNK in growth stimulation of hepatocytes. However, it is not known which factors regulate JNK activity in liver cells. In this study, we examined activation of JNK and p38 in HepG2 cells stimulated with heterotrimeric G protein-coupled receptor agonists known as mitogens. Thrombin, lysophosphatidic acid (LPA), and bradykinin (BK) stimulated extracellular signal-regulated protein kinase to similar extents, indicating that HepG2 cells have cell surface receptors for these agonists, which are coupled to intracellular signaling pathways. In contrast, only thrombin strongly activated JNK and p38. Thrombin-induced activation of JNK and p38 peaked at 30 minutes and 15 minutes with maximal stimulation of 13- and 4-fold increases, respectively. LPA and BK failed to activate JNK at all and activated p38 only slightly. Interestingly, thrombin-induced JNK activation was inhibited by protein kinase C down-regulation and the addition of a specific protein kinase C inhibitor. Short-term stimulation of cells with an active phorbol ester also induced JNK activation in HepG2 cells. These results indicate that thrombin is a relatively strong activator for JNK and p38 and might play a role in the regulation of activities of JNK and p38 in liver cells.

Bradykinin↗
PubMed1998

Dhh1p, a putative RNA helicase, associates with the general transcription factors Pop2p and Ccr4p from Saccharomyces cerevisiae.

The POP2 (Caf1) protein in Saccharomyces cerevisiae affects a variety of transcriptional processes and is a component of the Ccr4p complex. We have isolated five multicopy suppressor genes of a pop2 deletion mutation: CCR4, DHH1 (a putative RNA helicase), PKC1, STM1, and MPT5 (multicopy suppressor of pop two). Overexpression of either the CCR4 or DHH1 genes effectively suppressed phenotypes associated with pop2 mutant cells; overexpression of PKC1, STM1, or MPT5 genes produced only partial suppression. Disruption of the CCR4 or DHH1 genes resulted in phenotypes similar to those observed for pop2 cells. In addition, overexpression of the DHH1 gene also suppressed the ccr4 mutation, suggesting a close relationship between the POP2, CCR4, and DHH1 genes. Two-hybrid analysis and coimmunoprecipitation experiments revealed that Pop2p and Dhh1p interact physically, and these and other data suggest that Dhh1p is also a component of the Ccr4p complex. Finally, we investigated the genetic interaction between factors associated with POP2 and the PKC1 pathway. The temperature-sensitive growth defect of dhh1 or mpt5 cells was suppressed by overexpression of PKC1, and the defect of mpk1 cells was suppressed by overexpression of MPT5. These results and phenotypic analysis of double mutants from the POP2 and PKC1 pathways suggested that the POP2 and the PKC1 pathways are independent but have some overlapping functions.

Bacterial Proteins↗
PubMed1998

TAP polymorphism is not associated with ankylosing spondylitis and complications with acute anterior uveitis in HLA-B27-positive Japanese.

HLA-B27 is associated with the etiology of ankylosing spondylitis (AS) and acute anterior uveitis (AAU). Transporter associated with antigen processing (TAP) 1 and TAP2 polymorphism influences the range of peptide presented by HLA class I molecules. In this report, contribution of TAP polymorphism to the susceptibility to AS and AAU was studied in HLA-B27-positive Japanese individuals. Patients were classified into three groups: 16 AS patients, 14 AAU patients and 22 patients with both AS and AAU. Twelve HLA-B27-positive healthy individuals were included as a control. TAP polymorphism was detected by PCR-RFLP methods. Significant differences in frequencies of TAP1 alleles were not found between patient groups. None of the TAP2 frequencies showed increased or decreased frequencies compared with HLA-B27-positive healthy controls. In comparison with a random Japanese control, TAP2D allele frequency was significantly increased in the AAU group, but failed to reach a significant level in a group consisting of the AAU-only patients and the patients with both AS and AAU. All of the patient groups were noted to have a significantly increased prevalence of the TAP2H allele as compared to random controls; however, the higher frequency of this allele was detected in HLA-B27 healthy controls as well. These observations suggest a linkage disequilibrium between TAP2D, TAP2H and HLA-B27 in Japanese.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Dependence of activated Galpha12-induced G1 to S phase cell cycle progression on both Ras/mitogen-activated protein kinase and Ras/Rac1/Jun N-terminal kinase cascades in NIH3T3 fibroblasts.

We evaluated the roles of mitogen-activated protein kinase (MAPK) and Jun N-terminal kinase (JNK) signaling cascades in Galpha12-induced G1 to S phase cell cycle progression in NIH3T3(M17) fibroblasts. Transient expression of a constitutively active mutant of Galpha12, Galpha12(R203C), resulted in a 2-fold increase in the number of bromodeoxyuridine-positive S phase cells over vector control level under serum-deprived conditions. Consistent with the ability of Galpha12(R203C) to induce G1/S transition, its expression led to a 2-fold increase in cyclin A promoter activity, which showed a marked synergism with a low concentration of serum, resulting in up to a 15-fold elevation over the basal level. In addition, Galpha12(R203C) caused a 2-fold stimulation in E2F-mediated transactivation. Wild type Galpha12 showed similar stimulatory effects on cyclin A promoter activity and E2F-mediated transactivation, although of lesser magnitude. We observed a modest but constitutive activation of MAPK in cells transfected with Galpha12(R203C), which was abolished by a dominant negative form of Ras. Galpha12(R203C) also induced a 3-fold increase in JNK activity, which was abolished by dominant negative forms of either Rac1 or Ras. The expression of dominant negative forms of Ras, MAPK, Rac1, or JNK inhibited Galpha12(R203C)-induced increases in bromodeoxyuridine-positive cells. Also, the dominant negative forms of Ras, MAPK, and JNK strongly inhibited Galpha12(R203C)-induced stimulation of cyclin A promoter activity. These results demonstrate that both the Ras/MAPK and Ras/Rac1/JNK pathways convey necessary, if not sufficient, mitogenic signals induced by Galpha12 activation.

3T3 Cells↗
PubMed1997

Advances in soil microbial ecology and the biodiversity.

Recent studies on the colony formation of soil bacteria opened the way to categorize soil bacteria into colony forming curve (CFC) groups of different growth rates. A bacterial culture collection comprising organisms from every CFC group is called an ecocollection (EC). Outlines of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were described. Phylogenetic studies by 16S rDNA sequencing showed a great diversity of culture strains of the ecocollections. A set of alternative concepts was proposed; the active and the quiescent forms of bacterial cells in soil. The former is able to be cultivated and thus counted by the plate method, while the latter is not unless it transforms into the former. Based on the results several points required for extensive cataloguing of soil bacteria were noted.

Bacteria↗
PubMed1997

Manumycin and gliotoxin derivative KT7595 block Ras farnesylation and cell growth but do not disturb lamin farnesylation and localization in human tumour cells.

Recently, many inhibitors of farnesyl protein transferase (FPTase) have been identified. Some of them interrupt cell growth in addition to Ras and nuclear lamin processing of Ras-transformed cells. We have tested the effect of the FPTase inhibitors manumycin, an analogue of farnesyl diphosphate, and KT7595, a gliotoxin derivative, on Ras farnesylation, DNA synthesis and the anchorage-dependent and -independent growth of human colon carcinoma (LoVo), hepatoma (Mahlavu and PLC/PRF/5) and gastric carcinoma (KATO III). Both drugs severely inhibited DNA synthesis, cellular proliferation and Ras farnesylation in LoVo and moderately reduced them in Mahlavu and PLC/PRF/5 but not in KATO III. Complete sequencing of ras genes, however, revealed that LoVo and KATO III have activated Ki-ras and activated N-ras, respectively, whereas Mahlavu and PLC/PRF/5 have no activated ras. We next checked whether the inhibition of the cellular proliferation is due to the blocking of nuclear lamin function. Neither drug disturbed lamin farnesylation and localization, as demonstrated using metabolic labelling, immunoblotting and indirect immunofluorescence. These results indicate that manumycin and KT7595 can inhibit Ras farnesylation and cell growth without disturbing the farnesylation and localization of the lamins on human tumour cell lines.

Alkyl and Aryl Transferases↗
PubMed1997

A fraction unresponsive to growth inhibition by TGF-beta among the high-proliferative potential progenitor cells in bone marrow of p53-deficient mice.

Transforming growth factor-beta (TGF-beta) has been found to block the progression of the cell-cycle by up-regulating a Cdk inhibitor, p15, only in epithelial cells; on the other hand, wild-type p53 was shown to activate transcriptionally the gene for another Cdk inhibitor, p21. The regulatory effects of TGF-beta on hematopoietic tissues is poorly understood. Hence, we investigated the effect of TGF-beta on hematopoietic progenitor cells in p53-deficient mice to determine whether an inhibitory signal from TGF-beta is linked to p53 in hematopoietic regulation. We found that the proliferation of megakaryocyte-progenitors (CFU-Mk) in our wild-type mice was markedly inhibited by TGF-beta. Contrary to an earlier report, an erythroid and a granulocyte-macrophage progenitor, stimulated by IL-3, were not significantly inhibited, whereas TGF-beta also completely inhibited the growth of high-proliferative potential progenitor cells (HPP-CFC) in the marrow of mice with 5-fluorouracil (5FU), as reported. It is interesting that in the p53-deficient mice, the inhibitory action of TGF-beta on the HPP-CFC was incompletely abolished. The response curve we obtained for graded doses of TGF-beta suggests that there is, at least, a subpopulation of HPP-CFC which is less sensitive to the regulation by TGF-beta. In contrast to HPP-CFC, the CFU-Mk, which TGF-beta inhibited only in wild-type mice not treated with 5FU, remained inhibited in the p53-deficient strain. Thus, HPP-CFC might be regulated by TGF-beta through their signal pathways which are linked to p53.

Animals↗