Fragoso S P, Goldenberg S
Fundação Oswaldo Cruz, Dept. Bioquímica e Biologia Molecular, Laboratório de Expressão Gênica, Rio de Janeiro, Brazil.
Mol Biochem Parasitol. 1992 Oct;55(1-2):127-34. doi: 10.1016/0166-6851(92)90133-5.
The gene encoding Trypanosoma cruzi type II topoisomerase (TcTOP2) was isolated from a genomic library with a heterologous probe corresponding to part of the Trypanosoma brucei type II topoisomerase (TBrTOP2) gene. Nucleotide sequencing of TcTOP2 showed that the gene consists of an open reading frame of 3696 nucleotides (1232 amino acids), predicting a polypeptide product of 138,413 Da. Comparison of the amino acid sequence with that of type II topoisomerases from T. brucei (TBrTOP2) and Crithidia fasciculata (CfaTOP2), shows a high degree of conservation with estimated identities of 78% and 69%, respectively. TcTOP2 is a single copy gene in the genome of T. cruzi Dm28c and is expressed as a 4.5-kb mRNA. PCR mapping showed two distinct mini-exon addition sites at positions 225 and 203 upstream from the initiator AUG.
编码克氏锥虫II型拓扑异构酶（TcTOP2）的基因是从一个基因组文库中分离出来的，所用的异源探针对应于布氏锥虫II型拓扑异构酶（TBrTOP2）基因的一部分。TcTOP2的核苷酸测序表明，该基因由一个3696个核苷酸（1232个氨基酸）的开放阅读框组成，预测其多肽产物分子量为138413道尔顿。将该氨基酸序列与布氏锥虫（TBrTOP2）和fasiculata（CfaTOP2）的II型拓扑异构酶的氨基酸序列进行比较，发现它们具有高度的保守性，估计同源性分别为78%和69%。TcTOP2是克氏锥虫Dm28c基因组中的一个单拷贝基因，以4.5kb的mRNA形式表达。PCR定位显示，在起始AUG上游225和203位置有两个不同的小外显子添加位点。
