[Receptors for TGF-beta superfamily--a new signal transduction pathway of growth factor].
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Amino Acid Sequence↗
Biomedical subjects
N Ueno
Publications and source records attributed to N Ueno.
[Assessment of tumor extent in extrahepatic bile duct cancers--utility of intraductal ultrasonography].
Intraductal ultrasonography (IDUS) were performed in patients with extrahepatic bile duct cancer and compared to other diagnostic modalities and to resected specimens. Endoscopic ultrasonography (EUS) is a non-invasive diagnostic method useful for screening patients with bile duct cancers and determining whether they are resectable or not. While, EUS was not useful for the differential diagnosis of advanced and early tumors, and less useful in case of bile duct tumors located at the hilus hepatitis. IDUS proved useful without blind spot even in case of bile duct cancers at the hilus hepatis. IDUS was especially useful for the differential diagnosis of advanced and early tumors. IDUS is the very accurate diagnostic modality which make up for EUS and essential to determine the appropriate operation plan.
Aged↗
Evidence for singlet oxygen-induced cross-links and aggregation of collagen.
Singlet oxygen, generated by a hematoporphyrin-photosensitized reaction, was shown to cause insolubilization and an increase in molecular weight of acid soluble type I collagen and vitreous collagen as manifested in sodium dodecyl sulfate polyacrylamide gel electrophoresis. No such changes in the molecular properties of collagen could be observed when the irradiation was carried out in the presence of sodium azide, a singlet oxygen quencher. The increase in molecular weight and insolubilization of the collagen solution was attributed to extensive cross-links in the protein molecules.
Animals↗
Molecular orientation in thin films of bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole) on graphite studied by angle-resolved photoelectron spectroscopy.
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Journal Article↗
Biochemical properties of amphibian bone morphogenetic protein-4 expressed in CHO cells.
The biochemical properties of recombinant amphibian bone morphogenetic protein-4 (BMP-4), the cDNA of which has been cloned recently by screening of a Xenopus cDNA library, was characterized. The protein was expressed by the transfection of Chinese hamster ovary (CHO) cells with the cDNA cloned into expression vectors bearing a cytomegalovirus promoter or a simian virus 40 promoter. Northern-blot analysis showed that the latter vector was more efficient for Xenopus BMP-4 expression. Specific antiserum against Xenopus BMP-4 peptide demonstrated that the protein is synthesized as a large precursor, processed to the mature form and then secreted from the cells as a homodimer. Analysis of the biological activity in the conditioned medium revealed that Xenopus BMP-4 has a potent alkaline phosphatase-inducing activity on mouse osteoblastic cells.
Animals↗
Molecular mechanisms of posterior vitreous detachment.
To determine a molecular mechanism for posterior vitreous detachment and contraction of vitreous gel, the effects of serum components on bovine vitreous were systematically studied. Incubation of vitreous gel with calf serum caused a contraction of the gel accompanied by the release of a waterlike liquid. The low molecular weight fraction (M(r) < 10,000) of serum was ineffective in this process, whereas incubation of the vitreous with the high molecular weight fraction resulted in changes in the gel structure similar to those caused by serum alone. Individually, transglutaminase (factor XIIIa) was found to be most effective in inducing gel contraction. The effect was more pronounced when transglutaminase was used with fibronectin. Since transglutaminase is known to promote collagen-collagen or collagen-fibronectin-collagen cross-links, the contraction of the vitreous in this case can be attributed to the formation of similar cross-links.
Animals↗
Age-related changes in the molecular properties of vitreous collagen.
To understand the molecular events underlying rheological vitreous changes, age-related changes in the molecular properties of bovine and human vitreous collagen were monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The adult bovine vitreous showed an increase in the high molecular-weight components of the collagen compared with the young samples. In addition, the apparent molecular size of the alpha-chain of the adult type II collagen was slightly larger than that of the young samples. The same tendency also was observed in human vitreous. The increase of high-molecular-weight components of the vitreous collagen could be attributed to intermolecular cross-links of the peptide chains.
Adult↗
Presence of high molecular weight forms of BMP-2 in early Xenopus embryos.
Using polyclonal antibodies which recognize 18 kDa BMP-2, we have previously demonstrated that the major BMP-2 protein in Xenopus embryo extracts is monomeric and not dimerized whereas, the mammalian counterpart derived from bone extract was purified as a dimeric protein. In this study, the same antibodies (Ab383) were used to detect high molecular weight forms of Xenopus BMP-2. Partial purification of the immunoreactive 18 kDa BMP-2 from Xenopus embryo extract by gel filtration, heparin-Sepharose affinity chromatography and preparative SDS-PAGE resulted in co-purification and identification of higher molecular forms of BMP-2 of 110 kDa and 36 kDa. Diagonal SDS-PAGE analysis suggested that they are homodimer and multimer of the 18 kDa species, respectively, linked through disulfide bridge(s).
Animals↗
Immunodetection of Xenopus bone morphogenetic protein-4 in early embryos.
Specific antibodies to Xenopus laevis bone morphogenetic protein-4 (xBMP-4) were raised by immunizing rabbits with a fusion protein of bacterial beta-galactosidase and xBMP-4. The antibodies were used to detect xBMPs expressed in mammalian cells by Western blotting. The antibodies were found to recognize xBMP-4 specifically and not to cross-react with either xBMP-2 or xBMP-7 which are similar to xBMP-4. In addition, the antibodies recognized dimeric xBMP-4 whereas our previous antibodies recognized the reduced form only. The present antibodies detected an immunoreactive 27 kDa protein in extracts of developing Xenopus embryos from oocyte to tailbud embryo. The xBMP-4 peptide appeared to be monomeric in structure because the molecular weight did not shift upon reduction of disulfide bond(s).
Amino Acid Sequence↗
[Innervation of the external ear in humans and the musk shrew].
The external ear appears only in mammals and possesses a great diversity of forms. In addition, multiple nerves are distributed in the external ear. The nerves which are distributed in the external ear were investigated in humans and in the musk shrew (Suncus murinus) in a macroscopic study. The following results were obtained. Cranial nerves (CN) V, VII, X and cervical nerves supply the auricle and the external meatus in both humans and the musk shrew. Branches of the third division of CN V supply an anterior part of the external meatus and the anterior part of the auricle in both humans and the musk shrew. A branch of CN X, together with a branch of CN VII, supply the posterior parts of the external meatus in humans. In the musk shrew, a branch of CN X, together with a branch of CN VII, supplies the posterior part of the external meatus and the central part and the anterior portion of the auricle. Branches of the cervical nerve supply the posterior part of the auricle. Branches of the cervical nerve supply the posterior part of the external meatus and the central and posterior parts of the auricle in the musk shrew.
Aged↗
Differential expression of Xenopus BMPs in early embryos and tissues.
Expression levels of mRNA for Xenopus bone morphogenetic proteins (BMPs) in early embryos and adult organs were examined. Reverse transcription-polymerase chain reaction (RT-PCR) that used specific primers for each BMP subtype revealed that mRNAs for BMP-2 and BMP-4 are distributed in a wide variety of adult tissues including lung, heart, and kidney. Unexpectedly, distribution of mRNA for BMP-7 was found to be limited to ovary and early embryos. The result suggests that Xenopus BMP-7 may have a specific role in ovary and early embryos.
Animals↗
[A case of metastatic cancer of the stomach from small cell carcinoma of the lung].
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Aged↗
A carboxyl-terminal truncated version of the activin receptor mediates activin signals in early Xenopus embryos.
The function of a carboxyl-terminal truncated version of the Xenopus activin receptor, encoded by a previously isolated gene XSTK2, was investigated in early embryos. The transcript corresponding to the truncated receptor gene was detected throughout embryonic development although the temporal expression pattern was different from that of an intact receptor. Injection of XSTK2 mRNA into early embryos resulted in the formation of a duplicated body axis. Mesoderm induction as evaluated by the activation of the alpha-actin gene in presumptive ectoderm (animal cap) treated with exogenous activin was significantly enhanced by the injection of XSTK2 mRNA. These results suggest that the truncated receptor is capable of transmitting the activin signal to the same extent as the native receptor.
Actins↗
Genes for bone morphogenetic proteins are differentially transcribed in early amphibian embryos.
We have previously demonstrated that activin, a member of the TGF-beta family, has a potent mesoderm-inducing activity in Xenopus embryos. In the course of screening for activin-related genes from Xenopus, we have cloned cDNAs for Xenopus homologue of BMP-2, -4 and -7. Northern blot analysis revealed that these BMP genes are maternally encoded and differentially regulated after fertilization. Alkaline phosphatase-inducing assay using the recombinant BMP proteins has shown that at least BMP-2 and -4 have similar activity to mammalian counterparts.
Alkaline Phosphatase↗
Multiple genes for Xenopus activin receptor expressed during early embryogenesis.
Four distinct cDNAs for activin receptor designated as XSTK2, 3, 8 and 9 have been cloned from a Xenopus laevis cDNA library. The protein structures deduced from the cDNAs have shown that they all have a putative extracellular ligand-binding domain, a single transmembrane domain and cytoplasmic Ser/Thr kinase domain, except that XSTK2 is extremely similar to the XSTK3 gene but lacks a carboxyl-terminal part of the kinase motif. Northern blot analysis showed that all transcripts are maternally inherited. The levels of transcript for XSTK2, 3 and 8 appeared to fluctuate during early development while those for XSTK9 maintain constant.
Activin Receptors↗
Immunochemical evidence for the presence of advanced glycation end products in human lens proteins and its positive correlation with aging.
Prolonged incubation of protein with reducing sugar proceeds through a series of reactions involving early stage products to the advanced glycation end products with fluorescence, brown color, and cross-linking. Known collectively as the Maillard reaction, these changes have been suggested as factors in diabetic complications and the aging process. The early stage products have been demonstrated in vivo, but evidence for the presence in vivo of the advanced glycation end products has been limited. We sought to provide immunochemical evidence by the preparation and use of polyclonal and monoclonal antibodies to these end products (Horiuchi, S., Araki, N., and Morino, Y. (1991) J. Biol. Chem. 266, 7329-7332) as probes to identify and quantitate such compounds in human lens crystallins. Neither of the antibodies reacted with extracts from infant lenses, but fractions from adult lenses showed a significant reactivity, correlating with lens age. Our findings provide the first immunochemical evidence that human lens crystallins contain advanced glycation end products and that these products increase with tissue age.
Adult↗
Expression of thymosin beta 4 gene during Xenopus laevis embryogenesis.
In order to investigate the molecular events which take place during gastrulation, extracts from developing Xenopus embryos were analyzed for temporal peptide distribution by high performance liquid chromatography. One peptide peak which became increasingly dominant after gastrulation was purified and partially characterized. The amino acid sequence of enzymic digests showed the peptide is extremely similar to mammalian thymosin beta 4. The peptide was capable of binding actin monomers like mammalian counterparts. Cloning of the Xenopus thymosin beta 4 cDNA showed that only three amino acid substitutions occurred between amphibian and bovine. Northern blot analysis revealed the mRNA is maternally present at a low level and the transcript becomes abundant after gastrulation, supporting the distribution of the peptide.
Amino Acid Sequence↗
Functional regulation of osteoblastic cells by the interaction of activin-A with follistatin.
A high number of 125I-activin-A binding sites (an apparent Kd of 260 pM and 5,600 sites/cell) were observed on MC3T3-E1 cells, a well characterized osteoblastic cell line. Activin-A has a mitogenic effect on these cells, with the greatest influence being observed on cells in an undifferentiated state, as well as a suppressive effect on the alkaline phosphatase activity. Northern and ligand blotting analyses revealed that these osteoblastic cells produce follistatin, which was down-regulated by retinoic acid treatment. Because follistatin is an activin-A-binding protein, we suggest that activin-A modulates the function of osteoblastic cells by being regulated by follistatin during differentiation.
Activins↗