Analysis of 5′Untranslated Region in Trans‐Sialidase Annoted Sequences in the T.cruzi Genomes

Abstract

Trans‐sialidase (TS) is a membrane glycoprotein belonging to a family of genes from multiple copies involved in the process of cell invasion of the vertebrate host by the Trypanosoma cruzi (T. cruzi). Previous studies have shown that 5′ untranslated region is responsible for controlling gene regulation. In this work, we evaluated segments from TS cDNAs deposited in the Genbank‐dbEST such as the trans‐splicing additional or multiple sites, and their respective signals. We also investigated the compositional variation and the size of the sequences among T. cruzi epimastigotes strains: Dm28c (TcI), Y and CL‐Brener (TcII) and 4167 (Zymodeme 3). To corroborate these theoretical sequences, we acquired new test sequences based on RT‐PCR and qPCR. The fragments obtained from the different T. cruzi strains were cloned, sequenced and compositionally analyzed. CLUSTAL X was used to edit and align both theoretical and obtained sequences. All the TS theoretical sequences were searched against the dbEST database using BLAST program, which resulted in 735 cDNAs sequences. We also estimated the size of the mini‐exon‐containing fragments as 312 base pairs found in Z3, 209 in TcI and 218 in TcII. No mutations in the gene duplication presented in the trans‐splicing site were observed in the different strains. The qPCR analysis detected no differences in TS genes expression, although these genes are involved in host infectivity.