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101.
Kameda T Nakata A Mizutani T Terada K Iba H Sugiyama T 《Experimental cell research》2003,283(2):167-183
In the thin epidermis, the existence of epidermal proliferation units was hypothesized. Each unit is supposed to be partitioned into each column of polygonal-shaped cornified plates, estimated to contain a central stem cell in its basal layer. We attempted to verify this hypothesis in vitro by analyzing the partially decomposed fragment of mouse ear epidermis and in vivo using retroviral cell marking. Partially decomposed fragments of the mouse ear epidermis, mostly composed of cytokeratin 14-expressing basal keratinocytes, formed multicellular colonies in vitro. They were composed of heterogeneously shaped cells, morphologically resembling the cells in each single cell-derived colony, including potential stem cells with great proliferative potency in vitro. The estimated frequency of the candidates of stem cells in the fragments was much lower than the prediction from the representative hypothesis. Retroviral cell marking with nuclear localizing LacZ protein in vivo suggested the existence of a large clonal cellular unit for epidermal renewal. From these in vitro and in vivo observations, we propose a new model for the epidermal proliferation unit. 相似文献
102.
Hashiguchi S Nakashima T Nitani A Yoshihara T Yoshinaga K Ito Y Maeda Y Sugimura K 《Journal of biochemistry》2003,133(1):43-49
The alpha-chain of Fc epsilon RI (Fc epsilon RIalpha) plays a critical role in the binding of IgE to Fc epsilon RI. A fully human antibody interfering with this interaction may be useful for the prevention of IgE-mediated allergic diseases. Here, we describe the successful isolation of a human single-chain Fv antibody specific to human Fc epsilon RIalpha using human antibody phage display libraries. Using the non-immune phage antibody libraries constructed from peripheral blood lymphocyte cDNA from 20 healthy subjects, we isolated three phage clones (designated as FcR epsilon 27, FcR epsilon 51, and FcR epsilon 70) through two rounds of biopanning selection. The purified soluble scFv, FcR epsilon 51, inhibited the binding of IgE to recombinant Fc epsilon RIalpha, although both FcR epsilon 27 and FcR epsilon 70 showed fine binding specificity to Fc epsilon RIalpha. Since FcR epsilon 51 was determined to be a monomer by HPLC, BIAcore analysis was performed. The dissociation constant of FcR epsilon 51 to Fc epsilon RIalpha was estimated to be 20 nM, i.e., fortyfold lower than that of IgE binding to Fc epsilon RIalpha (K(d) = 0.5 nM). With these characteristics, FcR epsilon 51 exhibited inhibitory activity on the release of histamine from passively sensitized human peripheral blood mononuclear cells. 相似文献
103.
Kaneko Y Takeshita H Mogi K Nakajima T Yasuda T Itoi M Kuwano H Kishi K 《Journal of biochemistry》2003,134(5):711-718
The DNase I from canine pancreas was purified 260-fold to electrophoretic homogeneity with a 35% yield using three-step column chromatography. The activity of the purified enzyme was completely inhibited by 20 mM EDTA, an antibody specific to the purified enzyme and G-actin. A 1,373-bp cDNA encoding canine DNase I was constructed from the total canine pancreatic RNA using a rapid amplification of cDNA ends method, followed by sequencing. The mature canine DNase I protein was found to consist of 262 amino acids. A survey of DNase I in 13 different canine tissues revealed the highest levels of both DNase I enzyme activity and gene expression in the pancreas; therefore, the canine DNase I is of the pancreatic type. Phylogenetic and sequence identity analyses, studies of immunological properties and the tissue-distribution patterns of DNase I indicated that the canine enzyme is more closely related to the human DNase I than to other mammalian DNases I. Therefore, canine DNase I is found to be one of the best substitutes in studies of human DNase I. 相似文献
104.
105.
Filamentous bacteriophages of vibrios are integrated into the dif-like site of the host chromosome 总被引:3,自引:0,他引:3 下载免费PDF全文
Iida T Makino K Nasu H Yokoyama K Tagomori K Hattori A Okuno T Shinagawa H Honda T 《Journal of bacteriology》2002,184(17):4933-4935
The dif site is located in the replication terminus region of bacterial chromosomes, having a function of resolving dimeric chromosomes formed during replication. We demonstrate that filamentous bacteriophages of vibrios, such as f237 (Vibrio parahaemolyticus) and CTXphi (V. cholerae), are integrated into the dif-like site of host chromosome. 相似文献
106.
Shimoda K Kamesaki K Numata A Aoki K Matsuda T Oritani K Tamiya S Kato K Takase K Imamura R Yamamoto T Miyamoto T Nagafuji K Gondo H Nagafuchi S Nakayama K Harada M 《Journal of immunology (Baltimore, Md. : 1950)》2002,169(9):4707-4711
IFN-alpha inhibits B lymphocyte development, and the nuclear protein Daxx has been reported to be essential for this biological activity. We show in this study that IFN-alpha inhibits the clonal proliferation of B lymphocyte progenitors in response to IL-7 in wild-type, but not in tyk2-deficient, mice. In addition, the IFN-alpha-induced up-regulation and nuclear translocation of Daxx are completely abrogated in the absence of tyk2. Therefore, tyk2 is directly involved in IFN-alpha signaling for the induction and translocation of Daxx, which may result in B lymphocyte growth arrest and/or apoptosis. 相似文献
107.
Takahashi H Kobayashi T Sato-Nara K Tomita KO Ezura H 《Journal of experimental botany》2002,53(368):415-422
Antibodies against melon ethylene receptor, Cm- ERS1 was prepared. Cm-ERS1 protein formed a disulphide-linked homodimer and it was present in microsomal membranes but not in soluble fractions. Cm-ERS1 protein was present at high levels in melon fruit during early developmental stages. This transition pattern was also observed in another melon cultivar. 相似文献
108.
Sagane Y Watanabe T Kouguchi H Sunagawa H Obata S Oguma K Ohyama T 《Biochemical and biophysical research communications》2002,292(2):434-440
The nontoxic-nonhemagglutinin (NTNHA) component, in both isolated form and the neurotoxin (NT)/NTNHA complexed form, was prepared protease-free from toxin complexes produced by Clostridium botulinum type D strain 4947. NTNHA in both preparations was found to be spontaneously converted to the nicked NTNHA form leading to 15- and 115-kDa fragments with the excision of several amino acid residues at specific sites on SDS-PAGE during long-term incubation, while that of the NT/NTNHA/hemagglutinin complexed form remained unnicked single-chain polypeptides under the same conditions. Considering that the NTNHA preparation contained small amounts of the nicked form of NTNHA and the addition of trypsin accelerated the cleavage, it is speculated that a nicked form of NTNHA remaining after the purification and/or NTNHA itself catalyzes the cleavage of intact NTNHA. 相似文献
109.
The yeast Candida boidinii PEP4 and PRB1 genes, encoding proteinase A (PrA) and proteinase B (PrB), respectively, have been cloned and their primary structures were analyzed. The open reading frames of the PEP4 gene (1263 bp encoding a protein of 420 amino acids) and the PRBI gene (1683 bp encoding a protein of 560 amino acids) were found. The deduced amino acid sequences of PrA and PrB are very similar to Saccharomyces cerevisiae PrA and PrB (64% and 61% identities, respectively). Both PEP4 and PRBI genes were disrupted in the C. boidinii genome by one-step gene disruption. The resultant pep4delta and the pep4delta prb1delta strains lost protease activity when compared with the wild-type original strain. The constructed C. boidinii strains are expected to be useful hosts for heterologous protein production. 相似文献
110.
Michishita E Matsumura N Kurahashi T Suzuki T Ogino H Fujii M Ayusawa D 《Bioscience, biotechnology, and biochemistry》2002,66(4):877-879
We tested various thymidine analogues for induction of a senescence-like phenomenon in HeLa cells. CldU, BrdU, and IdU similarly induced the morphology of senescent cells and typical senescence markers. Thymidine analogues other than 5-halogenated forms caused only cell death. BrdU efficiently killed the cells in cooperation with irradiation with light and a brief treatment with Hoechst 33258, but CldU did not at all. 5-Halogenated thymidine analogues were thus shown to be specific inducers of cellular senescence in mammalian cells. 相似文献