Search tips
Search criteria

Results 1-14 (14)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Activation of OASIS family, ER stress transducers, is dependent on its stabilization 
Cell Death and Differentiation  2012;19(12):1939-1949.
Endoplasmic reticulum (ER) stress transducers transduce signals from the ER to the cytoplasm and nucleus when unfolded proteins accumulate in the ER. BBF2 human homolog on chromosome 7 (BBF2H7) and old astrocyte specifically induced substance (OASIS), ER-resident transmembrane proteins, have recently been identified as novel ER stress transducers that have roles in chondrogenesis and osteogenesis, respectively. However, the molecular mechanisms that regulate the activation of BBF2H7 and OASIS under ER stress conditions remain unresolved. Here, we showed that BBF2H7 and OASIS are notably unstable proteins that are easily degraded via the ubiquitin-proteasome pathway under normal conditions. ER stress conditions enhanced the stability of BBF2H7 and OASIS, and promoted transcription of their target genes. HMG-CoA reductase degradation 1 (HRD1), an ER-resident E3 ubiquitin ligase, ubiquitinated BBF2H7 and OASIS under normal conditions, whereas ER stress conditions dissociated the interaction between HRD1 and BBF2H7 or OASIS. The stabilization of OASIS in Hrd1−/− cells enhanced the expression of collagen fibers during osteoblast differentiation, whereas a knockdown of OASIS in Hrd1−/− cells suppressed the production of collagen fibers. These findings suggest that ER stress stabilizes OASIS family members and this is a novel molecular mechanism for the activation of ER stress transducers.
PMCID: PMC3504707  PMID: 22705851
ER stress response; BBF2H7; OASIS; degradation; HRD1
3.  Heterogeneity in residual function of MeCP2 carrying missense mutations in the methyl CpG binding domain 
Journal of Medical Genetics  2003;40(7):487-493.
Rett syndrome is a neurodevelopmental disorder with severe mental retardation caused by mutations in the MECP2 gene. Mutations in the MECP2 gene are also associated with other genetic disorders, including X linked mental retardation in males. Missense mutations identified so far are present primarily in the methyl CpG binding domain (MBD) of MECP2. Here, the functional significance of 28 MBD missense mutations identified in patients were analysed by transient expression of the mutant proteins in cultured cells. The effects of mutations were evaluated by analysis of the affinity of MeCP2 to pericentromeric heterochromatin in mouse L929 cells and on transcriptional repressive activity of MeCP2 in Drosophila SL2 cells. These analyses showed that approximately one-third (9/28) of MBD missense mutations showed strong impairment of MeCP2 function. The mutation of the R111 residue, which directly interacts with the methyl group of methyl cytosine, completely abolished MeCP2 function and mutations affecting ß-sheets and a hairpin loop have substantial functional consequences. In contrast, mutations that showed marginal or mild impairment of the function fell in unstructured regions with no DNA interaction. Since each of these mutations is known to be pathogenic, the mutations may indicate residues that are important for specific functions of MeCP2 in neurones.
PMCID: PMC1735522  PMID: 12843318
4.  Thrombin-induced expression of RANTES mRNA through protease activated receptor-1 in human synovial fibroblasts 
Annals of the Rheumatic Diseases  2002;61(9):834-837.
Methods: A semiquantitative reverse transcriptase-polymerase chain reaction and reporter gene assay were performed using cultured human synovial fibroblasts from patients with RA. The up regulatory effects of thrombin on RANTES mRNA expression were tested. In addition, the roles of protease activated receptors (PARs) were analysed.
Results: PAR-1 and PAR-3, but not PAR-4, were expressed in synovial fibroblasts. Thrombin induced RANTES mRNA expression in a time dependent manner in synovial fibroblasts expressing PAR-1. A reporter gene assay showed that thrombin-induced RANTES gene expression was through PAR-1, but not PAR-3.
Conclusions: Thrombin induced RANTES mRNA expression through a PAR-1 mediated pathway, possibly indicating that thrombin has an important role in migration of inflammatory cells by RANTES to the synovium in patients with RA.
PMCID: PMC1754231  PMID: 12176812
6.  Site-specific introduction of functional groups into phosphodiester oligodeoxynucleotides and their thermal stability and nuclease-resistance properties. 
Nucleic Acids Research  1997;25(14):2784-2791.
We report here the site-specific introduction of functional groups into phosphodiester oligodeoxynucleotides (ODNs). ODNs containing both 5-( N-aminohexyl)-carbamoyl-2'-deoxyuridine (H), which serves as a tether for the further conjugation of functional groups, and 5-(N,N-dimethylaminohexyl)carbamoyl-2'-deoxyuridine (D), which contributes to the thermal stability of the duplex and to the resistance to nucleolytic hydrolysis by nucleases, were synthesized. Functional groups such as folic acid and palmitic acid were site-specifically introduced into the terminus of the aminohexyl-linker of H. The thermal stability and resistance toward nuclease digestion of the modified ODNs were studied. We found that ODNs containing D and H formed stable duplexes with both the complementary DNA and RNA strands even when a bulky functional group such as folic acid, palmitic acid or cholesterol was attached to the terminus of the amino-linker. We also found that ODN analogues which contained D were more resistant to nucleolytic degradation by exo- and endonuclease than the unmodified ODN. Furthermore, duplexes formed by ODNs containing D and the complementary RNA could elicit RNase H activity.
PMCID: PMC146824  PMID: 9207025
7.  Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha. 
Infection and Immunity  1992;60(12):5253-5258.
Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recombinant human tumor necrosis factor alpha produced neutrophil chemotactic factors after 4 h, whereas expression of cell-derived IL-8 mRNA was detected within 1 h after stimulation. Furthermore, in a neutralization assay, rabbit anti-recombinant human IL-8 antiserum inhibited neutrophil chemotactic activity to basal levels. These results provide evidence that gingival fibroblasts synthesize potent chemotactic factors such as IL-8 in the presence of the inflammatory mediators interleukin-1 beta and tumor necrosis factor alpha. The activity of these factors may contribute to neutrophil-mediated processes in the pathogenesis of periodontal disease.
PMCID: PMC258304  PMID: 1452358
8.  Humoral immune response to an antigen from Porphyromonas gingivalis 381 in periodontal disease. 
Infection and Immunity  1991;59(8):2758-2762.
The humoral immune responses of patients with periodontitis were evaluated to characterize the host response to Porphyromonas gingivalis. A sonic extract of P. gingivalis 381 from whole cells was fractionated by gel chromatography and ion-exchange chromatography. The fractionated extracts were evaluated by Western blot (immunoblot) analyses with patient sera. A dominant antigen was identified from the sonic extract with an apparent molecular mass of 53 kDa. The 53-kDa protein antigen (Ag53) was purified by affinity chromatography by using a monoclonal antibody. Ag53 was detected on the vesicle surface of P. gingivalis 381 by immunoelectron microscopy by using the monoclonal antibody and was detected as a major protein in the outer membrane and in vesicles by Western blot analysis. Monoclonal antibody cross-reactivity to Ag53 in the sonic extracts of P. gingivalis ATCC 33277, P. gingivalis 1021, and Porphyromonas endodontalis ATCC 35406 was revealed. Seventy-seven patients with periodontitis were examined for their responses to Ag53. Serum immunoglobulin G (IgG) from 54 patients reacted strongly to Ag53; however, serum IgG from the remaining 23 patients did not exhibit detectable reactivity at all to Ag53, even though the patients had high serum IgG titers to the sonic extract. Ag53 is a new marker that represents an interesting aspect of the humoral immune response to P. gingivalis in patients with periodontitis.
PMCID: PMC258083  PMID: 1855992
9.  HLA antigens in Japanese patients with myasthenia gravis. 
Journal of Clinical Investigation  1990;86(2):392-399.
HLA antigens in 104 Japanese patients and 41 families with myasthenia gravis (MG) were investigated. The frequencies of DR9 and DRw13 were significantly increased in the patients who developed MG before 3 yr of age. The DQw3 antigen was positive for all the patients that developed MG before 15 yr with only one exception. All the examined cases that developed MG before 3 yr (including this DQw3 negative patient) had the same DQA and DQB DNA restriction fragments. These HLA frequencies decreased as the age of onset increased, and no significant association was observed in adult-onset MG. No patients had B8, DR3, and DQw2. The relative risk was higher for the DR9/DRw13 heterozygotes (37.4) than for DR9 (16.4) or DRw13 (7.1) in the childhood-onset MG. Statistical analysis suggested that DR9 and DRw13 (or DQw1 and DQw3) act synergistically in the disease development. Family study revealed diverse DR9 haplotypes. The most frequent DRw13 haplotype was Bw44-BFF-C4A3B1-DRw13-DQw1, which may be evolutionarily related to the caucasian B8-DR3-DQw2 haplotype. These results showed that MG in early childhood in Japanese individuals is genetically different from that in adulthood and that in caucasians.
PMCID: PMC296740  PMID: 1974553
10.  Gene expression analysis of rheumatoid arthritis synovial lining regions by cDNA microarray combined with laser microdissection: up-regulation of inflammation-associated STAT1, IRF1, CXCL9, CXCL10, and CCL5 
The main histological change in rheumatoid arthritis (RA) is the villous proliferation of synovial lining cells, an important source of cytokines and chemokines, which are associated with inflammation. The aim of this study was to evaluate gene expression in the microdissected synovial lining cells of RA patients, using those of osteoarthritis (OA) patients as the control.
Samples were obtained during total joint replacement from 11 RA and five OA patients. Total RNA from the synovial lining cells was derived from selected specimens by laser microdissection (LMD) for subsequent cDNA microarray analysis. In addition, the expression of significant genes was confirmed immunohistochemically.
The 14 519 genes detected by cDNA microarray were used to compare gene expression levels in synovial lining cells from RA with those from OA patients. Cluster analysis indicated that RA cells, including low- and high-expression subgroups, and OA cells were stored in two main clusters. The molecular activity of RA was statistically consistent with its clinical and histological activity. Expression levels of signal transducer and activator of transcription 1 (STAT1), interferon regulatory factor 1 (IRF1), and the chemokines CXCL9, CXCL10, and CCL5 were statistically significantly higher in the synovium of RA than in that of OA. Immunohistochemically, the lining synovium of RA, but not that of OA, clearly expressed STAT1, IRF1, and chemokines, as was seen in microarray analysis combined with LMD.
Our findings indicate an important role for lining synovial cells in the inflammatory and proliferative processes of RA. Further understanding of the local signalling in structural components is important in rheumatology.
PMCID: PMC3400100  PMID: 22401175
11.  Sse8387I, a new type-II restriction endonuclease that recognizes the octanucleotide sequence 5'-CCTGCAGG-3'. 
Nucleic Acids Research  1990;18(19):5637-5640.
A type II restriction endonuclease designated Sse8387I was partially purified from Streptomyces sp. 8387. This enzyme cleaved adenovirus 2 DNA at three sites, lambda phage DNA at five sites, and pUC18 and M13mp18 RF DNA at one site each, but did not cleave the DNAs from pBR322, SV40, or phi X174. Sse8387I recognized the octanucleotide sequence 5'-CCTGCA decreases GG-3', cleaving where shown by the arrow. Sse8387I is the first restriction endonuclease to be reported that recognizes an octanucleotide sequence consisting of all four nucleotides, G, A, T, and C. The frequency of occurrence of Sse8387I sites within sequenced regions of primate genomes was 2.4 times that of NotI sites.
PMCID: PMC332294  PMID: 2170941
13.  Sse8647I, a new type II restriction endonuclease from a Streptomyces species cutting at 5'-AG/GWCCT-3'. 
Nucleic Acids Research  1995;23(5):742-744.
We isolated and characterized a new type II restriction endonuclease which recognizes the palindromic heptanucleotide sequence 5'-AGGWCCT-3' and cleaves double-stranded DNA after the first G in the sequence from a microorganism belonging to Streptomyces species. This enzyme cleaves adenovirus 2 DNA at eight sites, but does not cleave lambda phage, pBR322, pUC18 and 19, M13mp18 and 19, SV40, ColE1 and phi X174 DNAs.
PMCID: PMC306753  PMID: 7708487

Results 1-14 (14)