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81.
Chen L Xie L Dai Y Xiong X Fan W Zhang R 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2004,139(4):669-679
Nacre formation is an ideal model to study biomineralization processes. Although much has been done about biomineralization mechanism of nacre, little is known as to how cellular signaling regulates this process. We are interested in whether G protein signaling plays a role in mineralization. Degenerate primers against conserved amino acid regions of G proteins were employed to amplify cDNA from the pearl oyster Pinctada fucata. As a result, the cDNA encoding a novel G(s)alpha (pfG(s)alpha) from the pearl oyster was isolated. The G(s)alpha cDNA encodes a polypeptide of 377 amino acid residues, which shares high similarity to the octopus (Octopus vulgaris) G(s)alpha. The well-conserved A, C, G (switch I), switch II functional domains and the carboxyl terminus that is a critical site for interaction with receptors are completely identical to those from other mollusks. However, pfG(s)alpha has a unique amino acid sequence, which encodes switch III and interaction sites of adenylyl cyclase respectively. In situ hybridization and Northern blotting analysis revealed that the oyster G(s)alpha mRNA is widely expressed in a variety of tissues, with highest levels in the outer fold of mantle and epithelia of gill, the regions essential for biomineralization. We also show that overexpression of the pfG(s)alpha in mammalian MC3T3-E1 cells resulted in increased cAMP levels. Mutant pfG(s)alpha that has impaired CTX substrate diminished its ability to induce cAMP production. Furthermore, the alkaline phosphatase (ALP) activity, an indicator for mineralization, is induced by the G(s)alpha in MC3T3-E1 cells. These results indicated that G(s)alpha may be involved in regulation of physiological function, particularly in biological biomineralization. 相似文献
82.
Lee Gap Ryol Kim Se Nyun Noguchi Kohei Park Sang Dai Hong Seung Hwan Cho-Chung Yoon S. 《Molecular and cellular biochemistry》1999,195(1-2):77-86
Expression of the RI regulatory subunit of protein kinase A type I is increased in human cancer cell lines, in primary tumors, in cells after transformation, and in cells upon stimulation of growth. Ala99 (the pseudophosphorylation site) of human RI was replaced with Ser (RI-p) for the structure-function analysis of RI. MCF-7 hormone- dependent breast cancer cells were transfected with an expression vector for the wild-type RI or mutant RI-p. Overexpression of RI-P resulted in suppression of protein kinase A type II, the isozyme of type I kinase, production of kinase exhibiting reduced cAMP activation, and inhibition of cell growth showing an increase in G0/G1 phase of the cell cycle and apoptosis. The wild-type RI overexpression had no effect on protein kinase A isozyme distribution or cell growth. Overexpression of protein kinase A type II regulatory subunit, RII, suppressed RI and protein kinase A type I and inhibited cell growth. These results show that the growth of hormone-dependent breast cancer cells is dependent on the functional protein kinase A type I. 相似文献
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85.
两种野生花卉的扦插繁殖研究 总被引:4,自引:0,他引:4
开展野生花卉车轮梅(Raphiolepis indica)和赤楠(Syzygium buxifolium)扦插试验,结果表明:车轮梅硬枝扦插需一定浓度的外源激素方能生根;对激素浓度大小不敏感;总体上NAA组合生根质量优于IBA组合。综合不同处理生根率、根数和不定根根长3个指标,以800 mg/L NAA或800 mg/L IBA作为车轮梅生产上扦插的激素种类和浓度。赤楠生根率较低,最高扦插率达66.7%,生根时间长,约需45 d始生根。综合生根率、不定根根数和不定根根长3个生根指标,试验的4种激素均能较好促进赤楠生根,200×根太阳在生根率和根数上效果最好,生产上可用200×根太阳浸泡2 h,也可用50-100 mg/L NAA或100-400 mg/L IBA浸泡2 h后进行扦插。 相似文献
86.
Jiang N Wang X Jhanwar-Uniyal M Darzynkiewicz Z Dai W 《The Journal of biological chemistry》2006,281(15):10577-10582
Polo-like kinase 3 (Plk3), an immediate early response gene product, plays an important role in the regulation of mitosis, DNA damage checkpoint activation, and Golgi dynamics. Similar to other members of the Plk family, Plk3 has a conserved kinase domain at the N terminus and a Polo box domain consisting of two Polo boxes at the C terminus. In this study, we demonstrate that the Polo box domain of Plk3 is sufficient for subcellular localization of this kinase to the centrosomes, the spindle poles, and the midbody when ectopically expressed in HeLa and U2OS cells. Both Polo boxes are required for the subcellular localization. Overexpression of the Polo box domain, not the kinase domain, of Plk3 causes significant cell cycle arrest and cytokinesis defects, eventually leading to mitotic catastrophe/apoptosis. Interestingly, the Polo box domain of Plk3 is more potent in inhibiting cell proliferation and inducing apoptosis than that of Plk1, suggesting that this domain can provide an additional structural basis for discovery of new anticancer drugs given the current emphasis on Plk1 as a therapeutic target. 相似文献
87.
增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)是一种优化的突变型GFP,DFL是从甘菊中分离出的LFY基因的同源序列。为了研究DFL基因的功能和表达模式,研究利用小片段克隆法将linker序列插入到EGFP基因5′端启始密码子前面,在pBI121载体的CaMV35S启动子的3′端后面插入一段多克隆位点,成功地构建了pBI-DFL-EGFP表达载体。通过设计特异引物,利用PCR技术扩增得了到拟南芥LFY基因的启动子序列,用粘性末端PCR技术将pBI-DFL-EGFP表达载体中CaMV35S启动子替换成LFY基因启动子,构建成了pLFY-DFL-EGFP表达载体。用含有pBI-DFL-EGFP和pLFY-DFL-EGFP质粒的农杆菌侵染洋葱表皮细胞,在荧光显微镜下分别用蓝光激发,均观测到了荧光。这一结果表明,融合蛋白DFL∷EGFP表达载体构建成功,同时还证明了通过PCR技术克隆到的LFY启动子序列具有启动子功能。 相似文献
88.
Shipan Dai Chhinder Sodhi Selma Cetin Ward Richardson Maria Branca Matthew D. Neal Thomas Prindle Congrong Ma Richard A. Shapiro Bin Li James H.-C. Wang David J. Hackam 《The Journal of biological chemistry》2010,285(7):4995-5002
Toll-like receptor-4 (TLR4) is the receptor for bacterial lipopolysaccharide, yet it may also respond to a variety of endogenous molecules. Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in newborn infants and is characterized by intestinal mucosal destruction and impaired enterocyte migration due to increased TLR4 signaling on enterocytes. The endogenous ligands for TLR4 that lead to impaired enterocyte migration remain unknown. High mobility group box-1 (HMGB1) is a DNA-binding protein that is released from injured cells during inflammation. We thus hypothesize that extracellular HMGB1 inhibits enterocyte migration via activation of TLR4 and sought to define the pathways involved. We now demonstrate that murine and human NEC are associated with increased intestinal HMGB1 expression, that serum HMGB1 is increased in murine NEC, and that HMGB1 inhibits enterocyte migration in vitro and in vivo in a TLR4-dependent manner. This finding was unique to enterocytes as HMGB1 enhanced migration of inflammatory cells in vitro and in vivo. In seeking to understand the mechanisms involved, TLR4-dependent HMGB1 signaling increased RhoA activation in enterocytes, increased phosphorylation of focal adhesion kinase, and increased phosphorylation of cofilin, resulting in increased stress fibers and focal adhesions. Using single cell force traction microscopy, the net effect of HMGB1 signaling was a TLR4-dependent increase in cell force adhesion, accounting for the impaired enterocyte migration. These findings demonstrate a novel pathway by which TLR4 activation by HMGB1 delays mucosal repair and suggest a novel potential therapeutic target in the amelioration of intestinal inflammatory diseases like NEC. 相似文献
89.
Guangyong Zheng ;Hong Li ;Chuan Wang ;Quanhu Sheng ;Haiwei Fan ;Shaoyou Yang ;Boshu Liu ;Jianliang Dai ;Rong Zeng ;Lu Xie 《Acta biochimica et biophysica Sinica》2009,(4):273-279
With the development of functional genomics research, large-scale proteomics studies are now widespread, presenting significant challenges for data storage, exchange, and analysis. Here we present the Integrated Proteomics Exploring Database (IPED) as a platform for managing proteomics experimental data (both process and result data). IPED is based on the schema of the Proteome Experimental Data Repository (PEDRo), and complies with the General Proteomics Standard (GPS) drafted by the Proteomics Standards Committee of the Human Proteome Organization. In our work, we developed three components for the IPED platform: the IPED client editor, IPED server software, and IPED web interface. The client editor collects experimental data and generates an extensible markup language (XML) data file compliant with PEDRo and GPS; the server software parses the XML data file and loads information into a core database; and the web interface displays experimental results, to provide a convenient graphic representation of data. Given software convenience and data abundance, IPED is a powerful platform for data exchange and presents an important resource for the proteomics community. In its current release, IPED is available at http://www. biosino.org/iped2. 相似文献
90.
Weimin Zhou Min Zhu Ming Gui Lihua Huang Zhi Long Li Wang Hui Chen Yinghao Yin Xianzhen Jiang Yingbo Dai Yuxin Tang Leye He Kuangbiao Zhong 《PloS one》2014,9(10)
Alterations of mitochondrial DNA (mtDNA) have been associated with the risk of a number of human cancers; however, the relationship between mtDNA copy number in peripheral blood leukocytes (PBLs) and the risk of prostate cancer (PCa) has not been investigated. In a case-control study of 196 PCa patients and 196 age-paired healthy controls in a Chinese Han population, the association between mtDNA copy number in PBLs and PCa risk was evaluated. The relative mtDNA copy number was measured using quantitative real-time PCR; samples from three cases and two controls could not be assayed, leaving 193 cases and 194 controls for analysis. PCa patients had significantly higher mtDNA copy numbers than controls (medians 0.91 and 0.82, respectively; P<0.001). Dichotomized at the median value of mtDNA copy number in the controls, high mtDNA copy number was significantly associated with an increased risk of PCa (adjusted odds ratio = 1.85, 95% confidence interval: 1.21–2.83). A significant dose-response relationship was observed between mtDNA copy number and risk of PCa in quartile analysis (Ptrend = 0.011). Clinicopathological analysis showed that high mtDNA copy numbers in PCa patients were significantly associated with high Gleason score and advanced tumor stage, but not serum prostate-specific antigen level (P = 0.002, 0.012 and 0.544, respectively). These findings of the present study indicate that increased mtDNA copy number in PBLs is significantly associated with an increased risk of PCa and may be a reflection of tumor burden. 相似文献