Songthamwat Dujdow, Kajihara Kazuo, Kikuchi Mihoko, Uemura Haruki, Tran Sieu Phu Manh, Yanagi Tetsuo, Higo Hiroo, Hirayama Kenji
Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
Parasitol Int. 2007 Dec;56(4):273-80. doi: 10.1016/j.parint.2007.05.004. Epub 2007 Jun 5.
The glycoprotein gp82 is a GPI-anchored cell surface protein of Trypanosoma cruzi and is involved in cell invasion. Gp82 is encoded by multiple genes. To investigate the genetic basis of its biological function, we analyzed structure and expression of gp82 multigene family members in the Peruvian and Guatemalan strains. Three major groups of gp82 genes (A, B and C) were categorized by analyzing multiple DNA clones from the genomic PCR products. Within each group, 95-97% homology was observed, whereas between the groups, homology was 67-79%. The copy numbers of groups A, B and C as determined by real-time PCR were 18, 8 and 7 copies, respectively, in the Peru-2 strain. Significant elevation of the mRNA expression levels (5-10 times more) of all the subfamily genes was observed in the metacyclic stage compared with the epimastigote stage. When we focused on the binding motif sequence reported previously, we found substantial difference between that of A and C. However, the peptide inhibition invasion assay showed no functional difference. Taken together, we demonstrated that three subfamilies of gp82 were in the genome of T. cruzi and maintained their functional structure, and that the mRNA expressions of those genes were equally controlled in a stage-specific manner.
糖蛋白gp82是克氏锥虫的一种糖基磷脂酰肌醇（GPI）锚定的细胞表面蛋白，参与细胞侵袭。Gp82由多个基因编码。为了研究其生物学功能的遗传基础，我们分析了秘鲁和危地马拉菌株中gp82多基因家族成员的结构和表达。通过分析基因组PCR产物中的多个DNA克隆，将gp82基因分为三大类（A、B和C）。在每组内，观察到同源性为95 - 97%，而在组间，同源性为67 - 79%。在秘鲁-2菌株中，通过实时PCR确定的A、B和C组的拷贝数分别为18、8和7个拷贝。与上鞭毛体阶段相比，在循环后期阶段观察到所有亚家族基因的mRNA表达水平显著升高（高5 - 10倍）。当我们关注先前报道的结合基序序列时，我们发现A和C的序列存在实质性差异。然而，肽抑制侵袭试验显示没有功能差异。综上所述，我们证明了gp82的三个亚家族存在于克氏锥虫基因组中并维持其功能结构，并且这些基因的mRNA表达以阶段特异性方式受到同等调控。
