番茄SlSL1重组蛋白的表达、纯化及体外泛素化活性检测

泛素化作为真核生物细胞内普遍存在且极为关键的蛋白质翻译后修饰,可以使被修饰的蛋白质发生降解,在植物生长发育、胁迫应答等方面发挥着重要作用。泛素化降解需要通过E3泛素连接酶特异性识别靶蛋白并对其进行修饰,因此E3连接酶在泛素化途径中起着决定性的作用。文章通过克隆番茄SlSL1基因编码序列、构建原核重组表达质粒,并利用诱导表达、亲和吸附纯化SlSL1重组蛋白,以此进行SlSL1的体外泛素化活性检测。SDS-PAGE电泳和考马斯亮蓝染色结果显示,由所构建番茄SlSL1基因重组质粒纯化获得SlSL1蛋白;体外泛素化检测显示,SlSL1蛋白形成多聚化泛素条带,具有E3泛素连接酶活性,表明SlSL1可能在番茄的泛素化调控途径中发挥功能。     

棉铃虫泛素基因的克隆及序列分析

泛素介导的泛素-蛋白酶体通路(Ubiquitin-proteasome pathway,UPP)是真核细胞内依赖ATP的非溶酶体蛋白质降解途径,该途径对细胞内蛋白的选择性降解起着重要作用.设计一对简并引物,从棉铃虫Helicoverpa armigera卵巢细胞Ha831中克隆了泛素基因的编码区,GenBank登录号AY456195.序列分析表明,该编码区的长度为228bp,编码76个氨基酸、其编码蛋白的相对分子质量为8 560,等电点为6.56.同源性比较发现,棉铃虫泛素基因与其他真核生物泛素基因在氨基酸水平上具有96%以上的相似性,而与棉铃虫核多角体病毒泛素的相似性为76%,所有已知的泛素关键功能位点在该泛素蛋白中均保守存在.     

E3泛素连接酶Pellino蛋白的研究进展

Pellino蛋白是近年来新发现的一类E3泛素连接酶,通过靶蛋白泛素化介导蛋白降解、蛋白与蛋白的相互作用、蛋白质细胞定位以及信号传导.目前研究表明Pellino蛋白在固有免疫细胞和获得性免疫细胞中具有重要调控作用,与炎症和自身免疫密切相关.本文总结了近年来Pellino蛋白的表达与活性调控、介导的信号转导途径以及在免疫...     

宿主细胞泛素系统与病毒相互作用的研究

真核细胞中,泛素系统执行对大多数短周期寿命蛋白的选择性降解,且已发现由泛素介导的对蛋白的降解调控在细胞的多种生命过程中起重要作用。病毒侵染宿主细胞后,细胞的泛素系统与一些重要的病毒蛋白相互作用,参与调节病毒的生活周期,如病毒迁移,核酸复制,免疫逃避,出芽等过程。     

26S蛋白酶体调控微管蛋白的降解

为了探究微管蛋白在植物细胞中的降解机制,本文利用微管解聚药物、蛋白酶体抑制剂MG132结合遗传学和分子生物学等体内体外研究技术发现微管蛋白TUA和TUB是通过泛素化/26S蛋白酶体途径降解的,同时在26S蛋白酶体调节亚基RPN10突变体rpn10-1的植株中,TUA的降解与野生型相比没有显著差别,但是TUB的降解在突变体中被严重削弱,使得TUB在突变体中过量积累.此外,在突变体中分别过量表达TUA和TUB,对转基因植株鉴定表明过量表达TUA促进突变体根的生长而过量表达TUB严重抑制了突变体的生长,说明在突变体中TUA/TUB的比例是失衡的,过量的TUB蛋白对植物的生长是不利的.以上结果表明,26S蛋白酶体可以调控微管蛋白TUA和TUB的降解,蛋白酶体调控亚基RPN10可以通过调控TUB的稳定性来影响植物的生长和发育.     

泛素-蛋白酶体途径的生物学功能

泛素—蛋白酶体途径通过降解许多诸如细胞周期因子、调节蛋白等蛋白,从而参与调节许多重要的生命活动。此途径的失调与许多人类疾病有关。针对此途径的研究为人类疾病预防和治疗提供了一个新思路。     

泛素在小鼠胚胎植入中的作用

选择lactacystin作为泛素(Ubiquitin,UPP)的抑制剂,采用宫角注射的方法,研究了UPP对小鼠胚胎植入的作用。结果表明,小鼠胚胎植入受UPP的影响。     

泛素-蛋白酶体通路的转化研究进展

泛素-蛋白酶体通路(UPP)负责细胞内大部分蛋白质的降解,在调整细胞周期、控制信号转导和调节细胞凋亡过程中起着至关重要的作用,并成为肿瘤治疗的靶标。该通路的转化研究促成第一代蛋白酶抑制剂的研发,以及临床应用治疗血液系统恶性肿瘤患者。     

GID/CTLH复合体的研究进展

GID/CTLH复合体是真核细胞中特有的具有E3泛素连接酶活性的大分子量蛋白复合体,深入分析其结构与功能具有重要的生物学意义。酵母GID复合体能帮助细胞快速应对微环境中营养状态的改变,同时在糖代谢调控中发挥重要作用;哺乳动物中的CTLH复合体能够迅速接收细胞外的不同信号,协调细胞发生可逆的变化,从而适应不断变化的环境,同时该复合体也涉及细胞内多个不同的生理途径的调控。本文综述了GID/CTLH复合体蛋白亚基的结构域、组成及功能的研究进展,旨在为该蛋白复合体的深入研究提供理论基础。     

Cdh1介导的Sp100蛋白降解机制初探(英文)

Cdh1是后期促进因子APC复合物的共激活因子之一,其蛋白在有丝分裂末期和G0/G1期激活APC复合物.Cdh1通过识别特异性的序列,在特定的细胞周期时刻为APC复合物呈递需要被降解的底物.Sp100作为PML-NBs结构重要组成蛋白,参与抗病毒,转录调控,细胞凋亡等重要的细胞活动.在本课题组前期研究工作中,发现了Sp100的蛋白序列上含有一个典型的D-box序列,即RxxL,暗示着Sp100能够被Cdh1识别,可能是APC复合物的底物.在本实验中,证明了Cdh1参与Sp100蛋白泛素化降解的途径,并且这个过程依赖于Sp100蛋白完整的D-box结构.这些发现不仅提供了一种新的内源的Sp100蛋白调控方式,并且为进一步研究Sp100以及其他PML-NBs蛋白的调节打下基础.     

Akt–Oct4 regulatory circuit in pluripotent stem cells

Oct4 is mainly expressed in embryonic stem cells(ESCs),germline stem cells,and embryonal carcinoma cells(ECCs)and plays an indispensable role in maintaining the pluripotency and self-renewal of these pluripotent stem cells.Akt serine/threonine kinase,a wellestablished anti-apoptosis and cell survival factor,has also been implicated as an important regulator of stemness.Emerging evidence indicated that Oct4 is reciprocally connected to Akt via a number of routes,and moreover,a direct interaction between Oct4 and Akt has recently been revealed.These components collectively form the Akt–Oct4 regulatory circuit.In this review,we summarize our current knowledge about the Akt–Oct4 regulatory circuit in ESCs and discuss its alterations in ECCs that may underlie the tumorigenesis of pluripotent stem cells.     

Identification and function analysis of spectrin-like protein in pollen tubes of lily （Lilium davidii Duch）

The elongation of pollen tube is an important process of sexual reproduction in higher plant. Cytoskeleton plays a major regulatory role in the elongation of pollen tubes. But whether membrane skeleton is involved in the pollen tube elongation is not clear. In this study, immunochemical detection of spectrin-like protein has been carried out in pollen tubes. By use of 2-dimensional electrophoresis(2DE) and western blotting, two spectrin-like proteins are found, one is 150 kD, and the other is 105 kD, with pl being 4.54 and 4.39, respectively. 150 kD spectrin-like protein is located in plasma membrane of pollen tube and 105 kD spectrin-like protein is located in cytoplasm, probably functioning as a subunit to form a dimmer (210 kD) in vivo. The elongation of pollen tubes is inhibited after spectrin antibody was injected into a growing pollen tube. These results suggest that spectrin-like proteins exist in pollen tube and play an important regulating role in the elongation process of pollen tubes from lily.     

人参皂甙的药理作用研究进展

人参皂甙是人参的主要有效成分,它具有多种功效,对于人体的多种器官、组织及细胞都具有重要的调控作用,包括滋补强身、安神益智功效,恢复疲劳、增强肌体免疫力,提高血液中血红素的含量及调节中枢神经系统等。     

均聚甲醛降解问题的探讨

对聚甲醛制品特别是均聚甲醛制品的降解在实验论证基础上，指出无论是均聚或者是共聚甲醛，在自然条件下都很难降解，并给出了降解的办法。     

Effects of ubiquitin-protea-some pathway on mouse sperm capacitation, acrosome reaction and in vitro fertilization

Chlortetracycline (CTC) fluorescence patterns were used to study changes in the patterns B and AR of mouse sperm after incubation with reagents that would block the UPP. They were the monoclonal antibody against ubiquitinated proteins-UCP1; the polyclonal antibody against ubiquitin anti-Ub, and a special inhibitor against proteasome ALLN. Furthermore, we treated the capacitated sperm or the eggs with these reagents separately and tested whether the normal in vitro fertilization was blocked or not. Results illustrate that UCP1, anti-Ub, and ALLN have little effects on sperm capacitation and acrosome reaction,but they do inhibit fusion of mouse sperm with eggs, which suggests that UPP play an important role in mouse in vitro fertilization.``     

胶孢炭疽菌RGS蛋白生物信息学分析

胶孢炭疽菌侵染众多植物引起的炭疽病,给各国农林业生产造成了巨大经济损失.RGS作为植物病原菌G蛋白信号转导过程中的重要调节因子,在众多生理生化过程中发挥着重要作用.本研究基于前期研究所获得的胶孢炭疽菌中所含有的12个RGS,通过保守结构域、理化性质、疏水性、细胞信号肽、跨膜区结构、亚细胞定位以及二级结构等生物信息学分析,明确上述RGS在保守结构域、理化性质、疏水性、信号肽、跨膜区域、二级结构等方面均具有较大的一致性特点;此外,通过对上述RGS进行遗传关系比较分析,发现不同菌株中的RGS彼此之间具有较近的亲缘关系.该研究为深入开展胶孢炭疽菌RGS功能研究打下坚实的理论基础.     

Effects of ubiquitin-proteasome pathway on mouse sperm capacitation, acrosome reaction and in vitro fertilization

Chlortetracycline (CTC) fluorescence patterns were used to study changes in the patterns B and AR of mouse sperm after incubation with reagents that would block the UPP. They were the monoclonal antibody against ubiquitinated proteins—UCP1; the polyclonal antibody against ubiquitin—anti-Ub, and a special inhibitor against proteasome—ALLN. Furthermore, we treated the capacitated sperm or the eggs with these reagents separately and tested whether the normal in vitro fertilization was blocked or not. Results illustrate that UCP1, anti-Ub, and ALLN have little effects on sperm capacitation and acrosome reaction, but they do inhibit fusion of mouse sperm with eggs, which suggests that UPP play an important role in mouse in vitro fertilization.