MORC4 is a novel breast cancer oncogene regulated by miR-193b-3p

A better understanding of breast cancer pathogenesis would contribute to improved diagnosis and therapy and potentially decreased mortality rates. Here, we found that the MORC family CW-type zinc finger 4 (MORC4) overexpression in breast cancer tissues is associated with poor survival, and the short-interfering RNA knockdown of MORC4 suppresses the growth of breast cancer cells by promoting apoptosis. To investigate the mechanisms associated with MORC4 upregulation, microRNAs potentially targeting MORC4 were analyzed, with miR-193b-3p identified as the regulator and a negative correlation between miR-193b-3p and MORC4 expression determined in both breast cancer cell lines and tissues. Further analysis verified that MORC4 silencing did not affect miR-193b-3p expression, although altered miR-193b-3p expression attenuated MORC4 protein levels. Moreover, dual-luciferase reporter assays verified miR-193b-3p binding to the 3′ untranslated region of MORC4. Furthermore, restoration of miR-193b-3p expression in breast cancer cells led to decreased growth and activation of apoptosis, which was consistent with results associated with MORC4 silencing in breast cancer cells. These results identified MORC4 as differentially expressed in breast cancer cells and tissues and its downregulation by miR-193b-3p, as well as its roles in regulating the growth of breast cancer cells via regulation of apoptosis. Our findings offer novel insights into potential mechanisms associated with breast cancer pathogenesis.     

水稻染色体标本制备的风油精法

水稻的染色体较小,不同的染色体在形态上较难区分。常规的压片技术由于很难使染色体分散,且也不能完全排除细胞质的干扰,因而很不适用于水稻染色体核型分析及显带。Kurata 等(1978)采用酶解与火焰干燥技术制备水稻染色体标本,获得清晰的染色体图象,从而成功地进行了水稻染色体的核型分析。陈瑞阳等(1982)参照人类染色体     

来源于铜绿假单胞杆菌(Pseudomonas aeruginosa)所产蛋白酶PT121克隆表达及其在小肽合成上的应用

【目的】基于前期筛选到的P.aeruginosa PT121所产有机溶剂耐受性蛋白酶,本研究对该蛋白酶进行克隆表达,研究了重组蛋白的酶学性质及小肽合成上的应用。【方法】参考文献中报道的相似蛋白酶pseudolysin设计引物从菌株PT121基因组中克隆到耐有机溶剂蛋白酶PT121基因las B。构建诱导表达重组质粒p ET22b-las B,于大肠杆菌中进行表达。考察蛋白酶PT121酶学性质及小肽合成上的应用。【结果】序列分析表明las B基因编码信号肽、前肽及成熟肽3个部分,成熟肽部分含有301个氨基酸,分子量约33 k Da,属于金属蛋白酶M4家族。通过破碎条件优化,一步法制备得到较为纯净的重组蛋白酶PT121,其比活力达7700 U/mg,该酶呈现了较高的热稳定性,p H稳定性及溶剂耐受性,与野生菌P.aeruginosa PT121所产蛋白酶性质一致。在50%DMSO体系中高效催化合成了多种小肽,其中阿斯巴甜前体(Cbz-Asp-Phe-NH2)产率高达91%。【结论】蛋白酶PT121基因在大肠杆菌中克隆表达为进一步研究相关催化机理及分子改造奠定了基础。     

Pleiotropic IFN-dependent and -independent effects of IRF5 on the pathogenesis of experimental lupus

Genetic polymorphisms of IFN regulatory factor 5 (IRF5) are associated with an increased risk of lupus in humans. In this study, we examined the role of IRF5 in the pathogenesis of pristane-induced lupus in mice. The pathological response to pristane in IRF5(-/-) mice shared many features with type I IFN receptor (IFNAR)(-/-) and TLR7(-/-) mice: production of anti-Sm/RNP autoantibodies, glomerulonephritis, generation of Ly6C(hi) monocytes, and IFN-I production all were greatly attenuated. Lymphocyte activation following pristane injection was greatly diminished in IRF5(-/-) mice, and Th cell differentiation was deviated from Th1 in wild-type mice toward Th2 in IRF5(-/-) mice. Th cell development was skewed similarly in TLR7(-/-) or IFNAR(-/-) mice, suggesting that IRF5 alters T cell activation and differentiation by affecting cytokine production. Indeed, production of IFN-I, IL-12, and IL-23 in response to pristane was markedly decreased, whereas IL-4 increased. Unexpectedly, plasmacytoid dendritic cells (pDC) were not recruited to the site of inflammation in IRF5(-/-) or MyD88(-/-) mice, but were recruited normally in IFNAR(-/-) and TLR7(-/-) mice. In striking contrast to wild-type mice, pristane did not stimulate local expression of CCL19 and CCL21 in IRF5(-/-) mice, suggesting that IRF5 regulates chemokine-mediated pDC migration independently of its effects on IFN-I. Collectively, these data indicate that altered production of IFN-I and other cytokines in IRF5(-/-) mice prevents pristane from inducing lupus pathology by broadly affecting T and B lymphocyte activation/differentiation. Additionally, we uncovered a new, IFN-I-independent role of IRF5 in regulating chemokines involved in the homing of pDCs and certain lymphocyte subsets.     

Intracellular expression of Vitreoscilla hemoglobin improves S-adenosylmethionine production in a recombinant Pichia pastoris

To develop an efficient way to produce S-adenosylmethionine (SAM), methionine adenosyltransferase gene (mat) from Streptomyces spectabilis and Vitreoscilla hemoglobin gene (vgb) were coexpressed intracellularly in Pichia pastoris, both under control of methanol-inducible promoter. Expression of mat in P. pastoris resulted in about 27 times higher specific activity of methionine adenosyltransferase (SMAT) and about 19 times higher SAM production relative to their respective control, suggesting that overexpression of mat could be used as an efficient method for constructing SAM-accumulating strain. Under induction concentration of 0.8 and 2.4% methanol, coexpression of vgb improved, though to different extent, cell growth, SAM production, and respiratory rate. However, the effects of VHb on SAM content (specific yield of SAM production) and SMAT seemed to be methanol concentration-dependent. When cells were induced with 0.8% methanol, no significant effects of VHb expression on SAM content and specific SMAT could be detected. When the cells were induced with 2.4% methanol, vgb expression increased SAM content significantly and depressed SMAT remarkably. We suggested that under our experimental scheme, the presence of VHb might improve ATP synthesis rate and thus improve cell growth and SAM production in the recombinant P. pastoris.     

A trypsin inhibitor from <Emphasis Type="Italic">Cassia obtusifolia</Emphasis> seeds: isolation,characterization and activity against <Emphasis Type="Italic">Pieris rapae</Emphasis>

A trypsin inhibitor was isolated from Cassia obtusifolia by ammonium sulfate precipitation, Sepharose 4B-trypsin affinity and Sephadex G-75 chromatography. The inhibitor consisted of a single polypeptide chain with a molecular mass of 19, 812.55 Da. It was stable from pH 2 to 12 for 24 h, whereas it was unstable either above 70°C for 10 min or under reduced conditions. The inhibitor, which inhibited trypsin activity with an apparent Ki of 0.3 μM, had one reactive site involving a lysine residue. The native inhibitor was resistant to pepsin digestion, whereas the heated inhibitor produced 40% degree of susceptibility. The disulfide linkage and lysine residue were important in maintaining its conformation. Partial amino acid sequence of the purified protein showed a high degree of homology with various members of the Kunitz inhibitor family. Moreover, the inhibitor showed significant inhibitory activity against trypsin-like proteases present in the larval midgut on Pieris rapae and could suppress the growth of larvae.     

糖蛋白组学研究技术进展及其应用

蛋白质的糖基化修饰与蛋白质功能密切相关,糖蛋白组学的相关研究已成为蛋白质组学研究的一个重要分支.本文在综述目前常用的糖蛋白组学技术方法的基础上,重点介绍了近两年出现的新技术策略及其应用.     

结球甘蓝和青花菜小孢子胚植株再生

结球甘蓝（Brassica oleracea var.capitata）和青花菜（Brassica oleracea var.italica）小孢子胚再生植株频率低是目前影响游离小孢子培养技术有效应用的关键问题之一,研究其小孢子胚植株再生频率的影响因素,提高胚再生植株频率,对促进游离小孢子培养技术在甘蓝类蔬菜育种中更好地应用具有重要意义。该文以结球甘蓝中甘11和青花菜TI-111等基因型为试材,对影响游离小孢子胚再生成植株的固体培养基类型、琼脂浓度、胚的类型及胚在液体培养基中的滞留时间等因素进行了研究。结果表明：游离小孢子培养25天的子叶胚在琼脂浓度为1%–1.25%的B5培养基上植株再生频率最高。进一步通过8个不同基因型对上述实验结果进行了验证,结果显示,游离小孢子培养25天的子叶胚在1%琼脂浓度的B5培养基上植株再生频率达77.8%–97.2%。