CHARACTERIZATION OF TRYPANOSOMA BRUCEI GP63 PROTEIN

布氏锥虫是非洲锥虫病的病原体，在其哺乳动物宿主的血流中细胞外增殖，但对补体介导的裂解（CML）具有抗性。这项研究的目的是确定T。布氏GP 63（Tb-GP 63）基因与CML的抗性关系。Tb-GP 63是利什曼原虫GP 63（L-GP 63）的同源物，L-GP 63是一种细胞表面锌金属蛋白酶，其对于利什曼原虫对CML的抗性至关重要。已鉴定出两组Tb-GP 63基因A和B。它们与L-GP 63以及彼此之间约有40%的相同性和60%的相似性。L-GP 63中的所有二硫键半胱氨酸和9个脯氨酸在Tb-GP 63-A和-B中是保守的，这表明Tb-GP 63蛋白质在结构上与L-GP 63相似。研究Tb-GP 63在T.将在杆状病毒表达系统中表达布鲁氏菌对CML的Tb-GP 63，并产生针对Th-GP 63的纯化抗体，并产生过表达或缺乏Tb-GP 63的细胞系。使用这些试剂。将解决以下问题：（i）Tb-Gp 63-A是功能性细胞表面蛋白酶吗？(ii)Tb-GP 63-B也是功能性GP 63同系物吗？(iii)Tb-GP 63是否能增加CML细胞的耐药性？(iv)Tb-GP 63是T.小鼠中的布氏杆菌？和（v）Tb-GP 63基因3'UTR是否调节Tb-GP 63的阶段特异性表达？这些研究可能为抗锥虫药物确定一个新的靶点，并将为T。布鲁氏菌是一种寄生虫。

Trypanosoma brucei, the causative agent of African trypanosomiasis, multiplies extracellularly in the bloodstream of its mammalian hosts but is resistant to complement mediated lysis (CML). The objective of this proposed research is to determine the role of T. brucei GP63 (Tb-GP63) genes in resistance to CML. Tb-GP63 is a homolog of leishmania GP63 (L- GP63), a cell surface zinc metalloprotease that is critical for the resistance of leishmania to CML. Two groups of Tb-GP63 genes have been identified A and B. which are approximately 40 % identical and 60 % similar to L- GP63 and to each other. All disulfide bonded cysteines in L-GP63 and nine prolines are conserved in Tb-GP63-A and -B, suggesting that the Tb-GP63 proteins will be structurally similar to L-GP63. To study the role of Tb- GP63 in the resistance of T. brucei to CML Tb-GP63 will expressed in a baculovirus expression system and purified antibodies will be generated against Th-GP63 and cell lines that over-express or that lack Tb-GP63 will be created. With these reagents. the following questions will be addressed: (i) is Tb-Gp63-A is a functional cell surface protease? (ii) is Tb-GP63-B also a functional GP63 homolog? (iii) does Tb-GP63 increase the resistance cells to CML? (iv) is Tb-GP63 is required for growth of T. brucei in mice? and (v) do the Tb-GP63 gene 3' UTRs regulate stage specific expression of Tb-GP63? These studies may identify a new target for anti-trypanosome drugs and will provide insight into the molecular basis for the success of T. brucei as a parasite.