Biomedical subjects

Ken-ichi Matsumoto

Publications and source records attributed to Ken-ichi Matsumoto.

8 recordsLinked to original sources

PubMed2006

Characterization of mouse serum tenascin-X.

The interstitial extracellular matrix tenascin-X (iTNX), which has a molecular mass of roughly 450 kDa, is expressed at high levels in muscular tissues and skin. In this study, we identified the serum form of TNX (sTNX) with a molecular mass of 200 kDa in the mouse. Western blot analysis with specific antibodies against fibronectin type III-like (FNIII) repeats of TNX and N-terminal sequence analysis of 200-kDa sTNX revealed that the N-terminus of sTNX is located in the juncture between the 16th FNIII (M16) and 17th FNIII (M17) repeats of iTNX. The 200-kDa sTNX contains 15 FNIII repeats and a fibrinogen domain identical to the Cterminal portion of the iTNX. TNX-deficient mice lacked not only iTNX but also sTNX. Furthermore, 200-kDa sTNX was generated by cleavage of the spleen iTNX by spleen homogenate, and its generation was inhibited by protease inhibitors. These results suggest that sTNX is generated by proteolytic cleavage of iTNX.

Amino Acid Sequence↗

PubMed2005

Positive regulation of Fas gene expression by MSSP and abrogation of Fas-mediated apoptosis induction in MSSP-deficient mice.

MSSP has been identified as a transcription factor that regulates the c-myc gene. MSSP was later found to positively or negatively regulate a variety of genes, including alpha-smooth actin, MHC class I, MHC class 2 and the thyrotropin receptor. The knockout mice for the Mssp gene developed by us revealed that these mice became partially embryonic lethal due to a low concentration of progesterone at E2.5. In this study, we further analyzed Mssp-knockout mice and found that the expression of the Fas gene was repressed, resulting in abrogation of Fas-mediated induction of apoptosis both in Mssp-knockout mice and primary thymocytes. MSSP was then found to stimulate promoter activity of the Fas gene by binding to a region spanning -1035 to -635 in chromatin immunoprecipitation assays. Binding of MSSP in the MSSP-binding sequence, TCTAAT, located in this region was confirmed by mobility shift assays, and deletion of this sequence from the Fas promoter was found to result in loss of MSSP-dependent stimulating activity. The results suggest that MSSP is an important mediator for Fas-induced apoptosis in vivo and in vitro.

Animals↗

PubMed2005

Transcription regulatory complex including YB-1 controls expression of mouse matrix metalloproteinase-2 gene in NIH3T3 cells.

Matrix metalloproteinase 2 (MMP-2) is a metalloproteinase belonging to a family of structurally related zinc-dependent endopeptidases capable of degrading extracellular matrix components. To elucidate the functional promoter of the mouse MMP-2 gene, systematic transient expression analysis of the 5'-flanking region of the MMP-2 gene was performed using serially nested deletions. The deletion analysis indicated that the proximal 327-bp sequence from nucleotide positions -313 to +14 relative to the transcription start site is essential for minimal promoter activity and that a 10-bp sequence of the promoter at positions -939 to -930 is required for high expression level of the MMP-2 gene. The 10-bp fragment functioned as a potent stimulator of heterologous SV40 promoter activity. This element is identical to the YB-1 binding motif (Y-box) present within the responsive element-1 (RE-1), which has been shown to act as a potent cis-activator of transcription of the rat MMP-2 gene. The binding of a nuclear factor(s) to the 10-bp fragment was also revealed by electrophoretic mobility shift assays (EMSAs). Antibody-supershift EMSAs of nuclear extracts from NIH 3T3 cells demonstrated YB-1 binding to the RE-1 sequence. It was concluded that the RE-1 is the conserved element for potent expression of MMP-2 gene among rodents.

3T3 Cells↗

PubMed2004

Self/nonself recognition in ascidian fertilization: vitelline coat protein HrVC70 is a candidate allorecognition molecule.

Ascidians are hermaphrodites releasing sperm and eggs simultaneously, but many species are self-sterile because of a self/nonself-recognition system in spermegg interaction. Here, we show that a 70-kDa vitelline coat protein, HrVC70, consisting of 12 epidermal growth factor-like repeats, plays a key role in self/nonself recognition during ascidian fertilization. We discovered that the amount of HrVC70 of the self-sterile mature oocytes is markedly higher than that of the self-fertile immature oocytes and that the selfsterile mature oocytes become self-fertile by acid treatment, which is able to release the HrVC70 from isolated vitelline coats. In addition, fertilization is strongly inhibited by the pretreatment of sperm with HrVC70 from a different individual, but not from the same individual, and the number of nonself sperm bound to HrVC70-agarose was significantly higher than that of self-sperm. A sequence analysis of HrVC70 disclosed that several amino acid residues in a restricted region are substituted at an individual level, with no identical sequences among the 10 individuals tested. Furthermore, genomic DNA analysis revealed that the epidermal growth factor-like domains correspond to the exons, and each intron is highly conserved among even- and odd-numbered introns, suggesting that multiple gene duplications or amplification of this region might have taken place during evolution. It was also found that diversity in cDNA sequences is derived from genomic DNA polymorphism probably elicited by crossing over and specific nucleotide substitutions. These results indicate that HrVC70 is a candidate allogeneic recognition molecule in the gamete interaction of the ascidian Halocynthia roretzi.

Amino Acid Sequence↗

PubMed2004

Modulation of collagen fibrillogenesis by tenascin-X and type VI collagen.

Tenascin-X (TNX) is an extracellular matrix glycoprotein. We previously demonstrated that TNX regulates the expression of type VI collagen. In this study, we investigated the binding of TNX to type I collagen as well as to type VI collagen and the effects of these proteins on fibrillogenesis of type I collagen. Full-length recombinant TNX, which is expressed in and purified from mammalian cell cultures, and type VI collagen purified from bovine placenta were used. Solid-phase assays revealed that TNX or type VI collagen bound to type I collagen, although TNX did not bind to type VI collagen, fibronectin, or laminin. The rate of collagen fibril formation and its quantity, measured as increased turbidity, was markedly increased by the presence of TNX, whereas type VI collagen did not increase the quantity but accelerated the rate of collagen fibril formation. Combined treatment of both had an additive effect on the rate of collagen fibril formation. Furthermore, deletion of the epidermal growth factor-like (EGF) domain or fibrinogen-like domain of TNX attenuated the initial rate of collagen fibril formation. Finally, we observed abnormally large collagen fibrils by electron microscopy in the skin from TNX-deficient (TNX-/-) mice during development. These findings demonstrate a fundamental role for TNX and type VI collagen in regulation of collagen fibrillogenesis in vivo and in vitro.

Animals↗

PubMed2004

Deficiency of tenascin-X causes a decrease in the level of expression of type VI collagen.

Tenascin-X (TNX) is an extracellular matrix glycoprotein. We previously demonstrated that TNX-null fibroblasts exhibit decreased cell-matrix and cell-cell adhesion. In this study, we used a differential display technique to determine the genes involved in this process. Differential display analysis of wild-type and TNX-null fibroblasts revealed that mRNA expression level of type VI collagen alpha3 is predominantly decreased in TNX-null fibroblasts. Expression levels of mRNAs of other subunits of type VI collagen, alpha2 and alpha3 chains, were also remarkably decreased in TNX-null fibroblasts. The protein level of alpha3 chain of type VI collagen was also reduced in TNX-null fibroblasts. However, the organization of type VI collagen in the extracellular matrix of TNX-null fibroblasts was similar to that of wild-type fibroblasts. Transient expression of TNX in Balb3T3 cells caused an increase in the level of mRNA of type VI collagen compared with that in vector control and increased the promoter activity of type VI collagen alpha1 subunit gene. In addition, the expression levels of type I collagen and other collagen fibril-associated molecules such as type XII and type XIV collagens, decorin, lumican and fibromodulin in wild-type and TNX-null fibroblasts were compared. It was found that the mRNA expression levels of type I collagen and collagen fibril-associated molecules other than decorin were decreased and that the expression level of decorin was increased in TNX-null fibroblasts. The results suggest the possibility that TNX mediates not only cell-cell and cell-matrix interactions but also fibrillogenesis via collagen fibril-associated molecules.

Animals↗

PubMed2004

Triglyceride accumulation and altered composition of triglyceride-associated fatty acids in the skin of tenascin-X-deficient mice.

Tenascin-X (TNX) is a member of the tenascin family of glycoproteins of the extracellular matrix. Here, we observed abnormalities in the skin of TNX-deficient mice in comparison with that of wild-type mice. Histological analysis with Oil Red O staining demonstrated that there was considerable accumulation of lipid in the skin of TNX-deficient (TNX-/-) mice. By thin-layer chromatography of total lipids, it was found that the level of triglyceride was significantly increased in TNX-/- mice. The mRNA levels of most of the lipogenic enzyme genes examined were remarkably increased in TNX-/- mice. By gas chromatography-mass spectrometry analysis of triglyceride-associated fatty acids in the skin, saturated fatty acid palmitoic acid was decreased, whereas unsaturated fatty acids palmitoleic acid and oleic acid were increased in TNX-/- mice compared with those in wild-type mice. Conversely, fibroblast cell lines transfected with TNX showed a significant decrease in the amount of triglyceride. An increase in the saturated fatty acid stearic acid and decreases in the unsaturated fatty acids palmitoleic acid, oleic acid and linoleic acid, compared to those in mock-transfected cells were also caused by over-expression of TNX. These results indicate that TNX is involved in the regulation of triglyceride synthesis and the regulation of composition of triglyceride-associated fatty acids.

Adipose Tissue↗

PubMed2002

DJ-1, a target protein for an endocrine disrupter, participates in the fertilization in mice.

DJ-1 was first identified as an activated ras-dependent oncogene product and was later also found to be an infertility-related protein affected by sperm toxicants such as ornidazole (OR) and epichlorohydrin. These findings suggest that DJ-1 has functions in both somatic cells and sperm. In this study, to determine the relationship between DJ-1 and an endocrine disrupter and to determine the functions of DJ-1 in sperm, in vitro fertilization experiments were carried out using eggs and sperm extracted from mice that had or had not been treated with OR. We found that the amount of DJ-1 in sperm and the efficiency of fertilization decreased with the increasing dose of OR to which the mice were exposed. The addition of an anti-mouse DJ-1 serum to sperm solution before the in vitro fertilization reaction with eggs resulted in a decrease in the efficiency of fertilization to about one-third of that when pre-immune serum was added to sperm solution, indicating that DJ-1 participates in the fertilization.

Animals↗