外遗传分子生物学研究进展

该文综述了外遗传 (Epigenetics)这一新的分子生物学研究领域的提出、发展和最新研究进展 .指出外遗传是DNA碱基序列之外的遗传系统 .阐述了DNA甲基化、RNA介导的基因沉默、基因组印记和组蛋白密码等外遗传相关因素在生物体生长发育过程中对基因表达的重要调控作用 ,以及这些因素与生物体的防御机制和生物遗传信息的传递间存在的密切联系 ,并提出了从外遗传角度探索物种进化和生物适应逆境的新途径 .     

组蛋白修饰调控植物水杨酸信号转导的研究进展

真核生物中组蛋白翻译后共价修饰直接影响染色质空间结构变化,调控相关基因表达,在植物胁迫应答过程中起重要作用。水杨酸(salicylic acid,SA)作为植物中关键信号分子,诱导多种病毒、真菌及细菌病害抗性。本文简要介绍了植物细胞对病原菌的感知、转导信号产生与防御系统激活机制,着重阐述了组蛋白甲基化、乙酰化、SUMO化修饰、组蛋白变体H2A.Z等如何参与调控水杨酸转导途径应答基因的转录表达。     

Tackling the Cytotoxic Effect of a Marine Polycyclic Quinone-Type Metabolite: Halenaquinone Induces Molt 4 Cells Apoptosis via Oxidative Stress Combined with the Inhibition of HDAC and Topoisomerase Activities

A marine polycyclic quinone-type metabolite, halenaquinone (HQ), was found to inhibit the proliferation of Molt 4, K562, MDA-MB-231 and DLD-1 cancer cell lines, with IC₅₀ of 0.48, 0.18, 8.0 and 6.76 μg/mL, respectively. It exhibited the most potent activity against leukemia Molt 4 cells. Accumulating evidence showed that HQ may act as a potent protein kinase inhibitor in cancer therapy. To fully understand the mechanism of HQ, we further explored the precise molecular targets in leukemia Molt 4 cells. We found that the use of HQ increased apoptosis by 26.23%–70.27% and caused disruption of mitochondrial membrane potential (MMP) by 17.15%–53.25% in a dose-dependent manner, as demonstrated by Annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of Molt 4 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by HQ, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of HQ. The results of a cell-free system assay indicated that HQ could act as an HDAC and topoisomerase catalytic inhibitor through the inhibition of pan-HDAC and topoisomerase IIα expression, respectively. On the protein level, the expression of the anti-apoptotic proteins p-Akt, NFκB, HDAC and Bcl-2, as well as hexokinase II was inhibited by the use of HQ. On the other hand, the expression of the pro-apoptotic protein Bax, PARP cleavage, caspase activation and cytochrome c release were increased after HQ treatment. Taken together, our results suggested that the antileukemic effect of HQ is ROS-mediated mitochondrial apoptosis combined with the inhibitory effect on HDAC and topoisomerase activities.     

非孟德尔遗传模式:表观遗传学及其应用研究进展

为了阐明表观遗传学在人类疾病发生发展过程中的应用,首先阐释表观遗传学主要研究内容。然后对肿瘤、阿尔兹海默病、动脉粥样硬化及糖尿病等疾病过程中DNA甲基化、组蛋白修饰、染色质重塑以及非编码RNA等表观遗传修饰的分子机制进行了总结概括。该研究对进一步理解相关疾病的发病机理及其分子调控机制有重要意义。     

苹果组蛋白脱乙酰化酶基因HDA19的生物信息学分析与胁迫响应研究

从‘嘎拉’苹果中克隆了MdHDA19（MDP0000132078）基因。它编码1个脱乙酰化酶,该基因ORF为1 494 bp,编码497个氨基酸,预测其蛋白质分子量为55.73 kD,等电点为4.98。进化树分析表明,HDA19在不同物种间的氨基酸序列保守性较高,其中苹果MdHDA19与可可树TcHDA19亲缘关系最近（87.05%）。MdHDA19表达模式分析显示,其在苹果各个器官中均有表达,尤其在根和花中表达量较高。MdHDA19与苹果中MdSAT18互作,MdHDA19受到盐胁迫诱导,可能参与盐胁迫的调控。MdHDA19表达受低温（4 ℃）和高温（40 ℃）诱导,说明MdHDA19可能参与调控苹果对温度胁迫的响应。并用原核诱导的方法在体外表达了MdHDA19蛋白。     

彭泽鲫Pcc-hira基因克隆、序列分析及时序表达（英文）

对雌核发育彭泽鲫(Carassius auratus var.Pengze,Pengze crucian carp,Pcc)中的Pcc-hira进行了克隆,序列分析,并对雌鱼9种组织和11个发育阶段中的表达进行了研究。结果显示,Pcc-hira CDS全长3028 bp,编码1009个氨基酸残基,具有7个典型WD40结构域,Pcc-HIRA与鲫HIRA具有99%的同源性,跟其他鲫属鱼具有较高的亲缘关系。Pcc-hira分别在孵化后36和44 d达到最高值和最低值,且在雌鱼脑中的含量极显著高于其他8种组织。     

白菜型油菜BraSDG8基因的克隆与序列分析

通过序列的同源性分析,在白菜型油菜中克隆得到拟南芥中的1个花期调控基因SDG8的全长cDNA,命名为BraSDG8.BraSDG8全长4 963 bp,编码1 654个氨基酸,其中第867位至第1 060位氨基酸连续构成AWS domain、SET domain、Post SET domain 3个结构域,与拟南芥中的...