Molecular mechanisms of diversity of theileria parasite genes distributed in middle and South America

瑟氏泰勒虫是一种蜱传的牛原虫。良性牛泰勒虫寄生虫，被认为是T。sergenti / buffeli / orientalis类群分布于亚洲国家。寄生虫具有主核质表面蛋白（MPSP）基因，MPSP基因是寄生虫逃避宿主免疫的手段之一，蜱是最重要的节肢动物类群之一，也是泰勒虫的传播媒介。为了比较分布于世界各地的蜱类唾液腺衍生分子，对唾液衍生分子如钙网蛋白（calreticulin）进行了分子克隆，钙网蛋白是一种具有抗补体和抗凝血酶活性的Ca<++>结合多功能蛋白。在这项研究中，钙网蛋白基因的蜱种扇头蜱，这是一个主要的载体T。在非洲引起东海岸热的细小病毒被清除。钙网蛋白cDNA克隆是从一株R.通过3'和5' RACE方法对AparylatuscDNA文库进行了分析。其核苷酸序列和推导的氨基酸序列与美洲钝眼蜱和微小Boopiylus microplus蜱的钙网蛋白基因具有较高的同源性。该基因的表达目前正在研究中。接下来，我们研究了丝氨酸蛋白酶抑制剂（serpins）的分子克隆。丝氨酸蛋白酶抑制剂在维持体内平衡中具有重要的调节作用，如凝血级联反应、纤维蛋白溶解、食物消化和受精。从H. longicornis和R.分别构建了Aparylulatus cDNA文库。这些克隆与其他蜱类或哺乳动物的丝氨酸蛋白酶抑制剂基因具有很高的同源性。这些基因在E.并进行生物活性测试。

Theileria sergenti is a tick-borne protozoa of cattle. Benign bovine theileria parasites, which are presumed to be of the T. sergenti / buffeli / orientalis group are distributed in Asian countries. The parasites have the major piroplasm surface protein (MPSP) gene which is one of the means of parasite evasion of host immunity.Ticks represent one of the most important groups of anthropods, and transmit theileria parasites. To compare the tick salivary gland derived molecules among ticks distributed all over the world, molecular cloning of saliva derived molecules, such as calreticulin, a Ca<++>-binding multifunctional protein showing anti-complement and anti-thrombin antivities. In this study, the calreticulin gene from a tick species Rhipicephalus appendiculatus, which is a major vector of T. parva causing East coast fever in Africa was clearified. A calreticulin cDNA clone was obtained from a R. appendiculatus cDNA library by the 3' and 5' RACE methods. The mucleotide and deduced amino acid sequences of the calreticulin genes showed high homology with those of known calreticulin genes of other tick species, Amblyoma americanum and Boopiylus microplus. The expression of this gene is now under investigation.Next, we examined the molecular cloning of serine proteinase inhibitors (serpins). Serpins are known to regulate important functions in maintenance of homeostasis, such as the blood coagulation cascade, fibrinolysis, food digestion and fertilization. Three and 4 serpin cDNAs were obtained from H. longicornis and R. appendiculatus cDNA libraries, respectively. These clones showed high homology with known serpin genes of other ticks or mammalian species. Expression of these genes in E. coli and examination of biological activities are now under investigation.