近日，中國(guó)科學(xué)院昆明動(dòng)物研究所張亞平院士指導(dǎo)的博士研究生吳東東及其合作者系統(tǒng)地獲得了瘧蚊基因組中的類(lèi)胰蛋白酶絲氨酸蛋白酶基因,，并和黑腹果蠅的基因相比較,，發(fā)現(xiàn)該家族在蚊子基因組中經(jīng)歷過(guò)適應(yīng)性擴(kuò)張。該類(lèi)基因的表達(dá)水平在吸血之后顯著升高,，并且擴(kuò)張的基因相對(duì)于進(jìn)化穩(wěn)定的基因的表達(dá)量升高較高,。同時(shí)，正選擇分析表明,，系統(tǒng)發(fā)育擴(kuò)張基因所受正選擇作用的位點(diǎn)主要分布在與蛋白酶抑制結(jié)合區(qū)域,。這些分析表明，類(lèi)胰蛋白酶絲氨酸蛋白酶基因?qū)ξ米游@一特性的適應(yīng)性進(jìn)化起著重要作用,。該研究具有重要的意義,。
蚊子是揮之不去，給人類(lèi)健康帶來(lái)許多威脅的害蟲(chóng),，其主要通過(guò)吸血來(lái)傳播各種疾病，如瘧疾,、絲蟲(chóng)病,、登革熱、黃熱病等,。類(lèi)胰蛋白酶絲氨酸蛋白酶(trypsin-like serine protease)是一廣泛存在于動(dòng)物界的基因家族,，主要行使消化功能，而其在蚊子消化血液的過(guò)程中起到重要作用,。伴隨著吸血過(guò)程,，蚊子體內(nèi)會(huì)發(fā)生很多生理上的變化，如基因表達(dá)量的升高或降低,。研究這類(lèi)發(fā)生變化的相關(guān)基因或元件有助于揭示蚊子吸血的機(jī)制,，進(jìn)而尋找到控制蚊子傳播疾病的有效方法。（生物谷Bioon.com）
生物谷推薦原始出處：
Molecular Biology and Evolution, doi:10.1093/molbev/msp139
A profound role for the expansion of trypsin-like serine protease family in the evolution of hematophagy in mosquito
Dong-Dong Wu1,3, Guo-Dong Wang1,3, David M Irwin4,5 and Ya-Ping Zhang1,2,3,*
1 State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
2 Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming 650091, China
3 Graduate School of the Chinese Academy of Sciences, Beijing, China
4 Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
5 Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
The trypsin-like serine protease (Tryp_SPc) family is ubiquitous in animals, and plays diverse roles, especially in the digestive system, in different phyla. In the mosquito, some Tryp_SPc proteases make important contributions to the digestion of the blood meal. Here, we have defined the complete Tryp_SPc gene repertoire in the genome of the malaria mosquito, a repertoire that has expanded remarkably compared to that of Drosophila. Phylogenetic analysis also indicates that the large scale lineage-specific expansion occurred leading to mosquitoes. Expression of Tryp_SPc genes elevates after a blood meal, and the expression level of genes that belong to subfamilies that specifically expanded on the mosquito lineage increased significantly more than genes that belong to subfamilies that did not expand in number, suggesting a profound role for the Tryp_SPc genes, especially the expanded subfamilies, in the hematophagous trait of the mosquito. The mosquito Tryp_SPc genes are mostly distributed in a tandem manner on chromosomes, suggesting a role for tandem duplication in the expansion of the subfamilies. Furthermore, evidence for positive selection was found for some genes. Structural modeling indicates that the positively selected sites locate to the surface that is conjugated by protein inhibitors. Our results suggest that the expansion and diversification of the Tryp_SPc domain family in mosquito was driven by positive selection and helps to explain the adaptive hematophagy of the mosquito.
