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131.
Kayoko Hayashihara Susumu Uchiyama Shigeru Shimamoto Shouhei Kobayashi Miroslav Tomschik Hidekazu Wakamatsu Daisuke No Hiroki Sugahara Naoto Hori Masanori Noda Tadayasu Ohkubo Jordanka Zlatanova Sachihiro Matsunaga Kiichi Fukui 《The Journal of biological chemistry》2010,285(9):6498-6507
In higher eukaryotic cells, DNA molecules are present as chromatin fibers, complexes of DNA with various types of proteins; chromatin fibers are highly condensed in metaphase chromosomes during mitosis. Although the formation of the metaphase chromosome structure is essential for the equal segregation of replicated chromosomal DNA into the daughter cells, the mechanism involved in the organization of metaphase chromosomes is poorly understood. To identify proteins involved in the formation and/or maintenance of metaphase chromosomes, we examined proteins that dissociated from isolated human metaphase chromosomes by 0.4 m NaCl treatment; this treatment led to significant chromosome decondensation, but the structure retained the core histones. One of the proteins identified, HP1-BP74 (heterochromatin protein 1-binding protein 74), composed of 553 amino acid residues, was further characterized. HP1-BP74 middle region (BP74Md), composed of 178 amino acid residues (Lys97–Lys274), formed a chromatosome-like structure with reconstituted mononucleosomes and protected the linker DNA from micrococcal nuclease digestion by ∼25 bp. The solution structure determined by NMR revealed that the globular domain (Met153–Thr237) located within BP74Md possesses a structure similar to that of the globular domain of linker histones, which underlies its nucleosome binding properties. Moreover, we confirmed that BP74Md and full-length HP1-BP74 directly binds to HP1 (heterochromatin protein 1) and identified the exact sites responsible for this interaction. Thus, we discovered that HP1-BP74 directly binds to HP1, and its middle region associates with linker DNA at the entry/exit site of nucleosomal DNA in vitro. 相似文献
132.
Takao S Ishikawa T Yamashita K Uchiyama T 《Journal of immunology (Baltimore, Md. : 1950)》2010,185(10):6031-6040
Increasing evidence shows that NK cells regulate adaptive immunity, but the underlying mechanisms are not well understood. In this study, we show that activated human NK cells suppress autologous naive CD4 T cell proliferation in response to allogeneic dendritic cells (DCs) by selectively killing Ag-activated T cells. Naive CD4 T cells, which were initially resistant to NK cell-mediated cytotoxicity, became substantially susceptible to NK cells within a day after priming with DCs. Ag-activated T cells showed various degrees of susceptibility to NK cells. After 1 d of priming with LPS-matured DCs, T cells were less susceptible to NK cells than were T cells primed with TNF-α-matured DCs. Subsequently at day 3, Ag-activated T cells regained resistance to NK cells. The level of HLA-E expression on Ag-activated T cells was closely correlated with resistance to NK cells. HLA-E was highly expressed at day 1 by T cells primed with LPS-matured DCs but not by T cells primed with TNF-α-matured DCs. An Ab blockade revealed a critical role for the HLA-E-NKG2A interaction in the protection of Ag-activated T cells from NK cells. Collectively, this study demonstrates that NK cells impact adaptive immunity through the finely controlled kinetics of HLA-E expression on T cells. Thus, HLA-E may be a new target for immunoregulation. 相似文献
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134.
Matsuda K Miura T Kaiya H Maruyama K Shimakura S Uchiyama M Kangawa K Shioda S 《Peptides》2006,27(9):2321-2325
Our recent research has indicated that intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of n-octanoic acid-modified ghrelin (acyl ghrelin) stimulates food intake and locomotor activity in the goldfish. The manner in which peripherally administered acyl ghrelin regulates food intake, however, remains unclear. In contrast to acyl ghrelin, non-acylated ghrelin (des-acyl ghrelin) does not exert an orexigenic action or induce hypermotility. To this extent, the biological role of des-acyl ghrelin in fish is unknown. Given the possible involvement of afferent pathways in mediating the effects of acyl ghrelin, as is known to occur in rodents, we examined the effect of capsaicin, a neurotoxin which destroys primary sensory (vagal and splanchnic) afferents, on the orexigenic activity induced by i.p.-injected acyl ghrelin. Pretreatment with i.p.-injected capsaicin (0.16 micromol/g body weight (BW)) cancelled the orexigenic action of i.p.-injected acyl ghrelin (8 pmol/g BW), although i.p.-injected capsaicin alone did not affect food intake. The effect of des-acyl ghrelin on the orexigenic action of acyl ghrelin in the goldfish was also investigated. The i.c.v. and i.p. injection of des-acyl ghrelin at doses 3-10 times higher than that of acyl ghrelin suppressed the orexigenic action of i.c.v.- and i.p.-injected acyl ghrelin (doses of 1 and 8 pmol/g BW). In contrast, injection of des-acyl ghrelin alone did not show any inhibitory effect on food intake. These results suggest that, as is seen in rodents, circulating acyl ghrelin derived from peripheral tissues acts via primary sensory afferent pathways on feeding centers in the brain. The results also show that des-acyl ghrelin inhibits acyl ghrelin-induced orexigenic activity in goldfish. 相似文献
135.
136.
Tanabe Y Hatada K Naito N Aizawa Y Chinushi M Nawa H Aizawa Y 《Biochemical and biophysical research communications》2006,345(3):1116-1121
BACKGROUND: Genetically abnormal action potential duration (APD) can be a cause of arrhythmias that include long and short QT interval syndrome. PURPOSE: The aim of this study was to evaluate the arrhythmogenic effect of short QT syndrome induced by the over-expression of Kv1.5 in rat. METHODS: From Sprague-Dawley rats on fetal days 18-19, cardiomyocytes were excised and cultured with and without transfection with the Kv-1.5 gene using an adenovirus vector. The expression of Kv1.5 was proven by immunohistochemistry and Western blot analysis. In the culture dish and in the whole cells, the electrical activities were recorded using the whole-cell patch-clamp technique and the effects of 4-AP and verapamil were tested. RESULTS: After transfection with Kv1.5 for 12h, immunohistochemical staining and Western blot analysis were positive for Kv1.5 while they were negative in the control transfected with only Lac-Z. In the culture dish, the myocytes showed spontaneous beating at 115beats/min (bpm) just prior to the transfection with Kv1.5 and increased to 367bpm at 24h. The control myocytes showed stable beating rates during culturing. 4-AP at 200microM slowed down the rate and verapamil abolished the beating. In the whole cells, the maximal resting membrane potential was slightly depolarized and APD was extremely abbreviated both at 50% and 90% of repolarization compared with those of the control. Rapid spontaneous activities were found in a single myocyte with Kv1.5 transfection and 4-AP slowed down the frequency of the activities with a reversal of the shortened APD. CONCLUSION: The over-expression of Kv1.5 induced short APD and triggered activities in rat cardiomyocytes. This model can be used to study the arrhythmogenic substrate of short QT syndrome. 相似文献
137.
Asai Takami Kaneita Yoshitaka Uchiyama Makoto Takemura Shinji Asai Satoshi Yokoyama Eise Miyake Takeo Harano Satoru Suzuki Kenshu Ibuka Eiji Kaneko Akiyo Tsutsui Takako Ohida Takashi 《Sleep and biological rhythms》2006,4(1):55-62
Sleep and Biological Rhythms - There have been only a few studies on the relationship between sleep disturbances and somatic and psychological complaints in Japanese people. In this study, we... 相似文献
138.
139.
Hiroaki Matsubara Yasunobu Shibasaki Mitsuhiko Okigaki Yasukiyo Mori Hiroya Masaki Atsushi Kosaki Yoshiaki Tsutsumi Yoko Uchiyama Soichiro Fujiyama Atsuko Nose Osamu Iba Eriko Tateishi Takamasa Hasegawa Masatsugu Horiuchi Clara Nahmias Toshiji Iwasaka 《Biochemical and biophysical research communications》2012,417(4):1316-1317
140.
Local adaptation is important in evolutionary processes and speciation. We used multiple
tests to identify several candidate genes that may be involved in local adaptation from
1026 loci in 14 natural populations of Cryptomeria japonica, the most
economically important forestry tree in Japan. We also studied the relationships between
genotypes and environmental variables to obtain information on the selective pressures
acting on individual populations. Outlier loci were mapped onto a linkage map, and the
positions of loci associated with specific environmental variables are considered. The
outlier loci were not randomly distributed on the linkage map; linkage group 11 was
identified as a genomic island of divergence. Three loci in this region were also
associated with environmental variables such as mean annual temperature, daily maximum
temperature, maximum snow depth, and so on. Outlier loci identified with high significance
levels will be essential for conservation purposes and for future work on molecular
breeding. 相似文献