摘要
分离和研究疟疾感染蚊的差异表达基因 ,对阐明媒介与疟原虫之间相互作用及其分子机制尤为重要。利用已建立的斯氏按蚊感染约氏疟原虫的差减cDNA库的进行表达筛选 ,发现表达增高基因中有一个编码与黑腹果蝇泛素羧端水解酶高度同源蛋白的序列。相似性比较显示该编码序列在氨基酸水平与已知的冈比亚按蚊EST序列对应部位的同源性为 89% ,与果蝇和人类的同源性均为 63%。模拟Northern印迹的表达动态分析提示 ,感染后至少 1～ 7天内该基因在蚊体内的表达显著增高 ,与疟原虫发育动合子穿越蚊中肠壁和子孢子从卵囊向蚊眼涎腺移行等关键阶段相一致。目前对有关蚊天然免疫系统激活的泛素途径所知甚少 ,现有结果提示该基因与疟原虫感染相关 。
The isolation and study of genes that are differentially expressed in malaria infected mosquitoes is important for the elucidation of basic molecular mechanisms underlying vector parasite interactions. When screening against a previously established cDNAs pool representing specifically expressed genes in the mosquito Anopheles stephensi infected by Plasmodium yoelii, it was found that one of these encodes a protein with extensive sequence similarity to the Drosophila melanogaster ubiquitin C terminal hydrolase(UCTH). Similarity alignment showed that the fragment is 89% identical at amino acid level to the corresponding region of the known An. gambiae EST sequence, as well as 63% identical to that of both the fruitfly and human sequence. Virtual Northern blot expression dynamics of the gene indicated that it was up regulated significantly in the mosquito at least 1 7 days post infection, consistent with the critical transition stages of midgut invasion and relocation of sporozoites from the oocysts to the salivary glands during parasite development. Rather little is known about the role of the ubiquitin pathway in the activation of the mosquito innate immune system. The results indicate that the gene is related to malaria infection in mosquito. The cloning and expression profile analysis of As UCTH enables us to make predictions as to the roles it may play during malaria infection.
