Heras S R, Thomas M C, García-Canadas M, de Felipe P, García-Pérez J L, Ryan M D, López M C
Departamento de Biología Molecular, Instituto de Parasitología y Biomedicina López Neyra, CSIC. P.T. de Ciencias de la Salud. Avda. del Conocimiento s/n, 18100 Armilla, Granada, Spain.
Cell Mol Life Sci. 2006 Jun;63(12):1449-60. doi: 10.1007/s00018-006-6038-2.
A comparative analysis of 40 Trypanosoma cruzi L1Tc elements showed that the 2A self-cleaving sequence described in viruses is present in them. Of these elements, 72% maintain the canonical 2A motif (DxExNPGP). A high percentage has a conserved point mutation within the motif that has not been previously described. In vitro and in vivo expression of reporter polyproteins showed that the L1Tc2A sequence is functional. Mutations within certain L1Tc2A sequences affect the efficiency of the cleavage. The data indicate that the L1Tc2A sequence may be influencing the L1Tc enzymatic machinery determining the composition and level of the translated products. The residues located immediately upstream of the 2A consensus sequence increase the cleaving efficiency and appear to stabilize the relative amount of translated products.
对40个克氏锥虫L1Tc元件的比较分析表明，病毒中描述的2A自切割序列存在于这些元件中。在这些元件中，72%保持了典型的2A基序（DxExNPGP）。很大比例的元件在该基序内有一个先前未描述的保守点突变。报告多聚蛋白的体外和体内表达表明，L1Tc2A序列具有功能。某些L1Tc2A序列内的突变会影响切割效率。数据表明，L1Tc2A序列可能正在影响决定翻译产物组成和水平的L1Tc酶机制。位于2A共有序列紧邻上游的残基提高了切割效率，并且似乎稳定了翻译产物的相对量。
