Screening of proteins that interact with human thrombopoietin receptor c-Mpl using yeast two-hybrid system

Thrombopoietin (TPO) is the major cytokine involved in platelet production and exerts its effects via the receptor c-Mpl. The yeast two-hybrid system has been used to screen the proteins interacting with c-Mpl. First, the cDNA fragment of c-Mpl intracellular domain was cloned into two-hybrid vector pAS2, and the resulting plasmid is designated as pASMM. Then a human placenta cDNA library was screened using the pASMM as a target plasmid. Seven positive clones were isolated from 150 000 independent transformants. Sequence analysis of one of the positive clones demonstrates that a part of coding sequence of vimentin from 611 bp to 3' end and flanking non-translation region was obtained. Therefore, there is an interaction between vimentin and TPO receptor. The results suggest that cytoskeletal protein may play an important role in TPO signal transduction pathway.     

用酵母双杂合系统筛选与人血小板生成素受体c-Mpl相互作用的蛋白质

血小板生成素(thrombopoietin,TPO)是调节血小板生成最主要的细胞因子,其生物学效应由其受体c-Mpl介导.利用酵母双杂合系统(two-hybrid system)筛选与c-Mpl相互作用的蛋白质因子.首先将c-Mpl膜内部分cDNA克隆至pAS2双杂合载体中,重组质粒命名为pASMM;然后以pASMM为靶蛋白质粒,筛选了人胎盘cDNA文库.在1.5×106个转化子中筛选到7个阳性克隆.序列测定表明,分离到编码人波形纤维蛋白(vimentin)的第611 bp至C末端的cDNA顺序(包括3'非翻译区),从而发现波形纤维蛋白可与TPO受体相互作用,这提示细胞骨架蛋白在TPO的信号转导过程中可能起着重要的作用.     

沃尔巴克氏体在中国三种稻飞虱中的感染

用PCR方法检测了采集于不同地域稻田的3种稻飞虱共生菌沃尔巴克氏体(Wolbachia)的感染,发现灰飞虱Laodelphax striatellus、褐飞虱Nilaparvata lugens、白背飞虱Sogatella furcifera为沃尔巴克氏体所感染。克隆了编码沃尔巴克氏体外膜蛋白质的wsp基因并进行了序列测定。对wsp的RFLP分析证实了这些飞虱为单一沃尔巴克氏体感染。研究了灰飞虱中沃尔巴克氏体所诱导的胞质不相容性及其在不同地域灰飞虱中的分布。还发现能寄生于上述3种飞虱的稻虱红螯蜂也受同种沃尔巴克氏体感染。沃尔巴克氏体可能通过这种寄生蜂在不同昆虫间横向传播。