Genomic Organization and Generation of Genetic Variability in the RHS (Retrotransposon Hot Spot) Protein Multigene Family in Trypanosoma cruzi

Werica P Bernardo,José Luis Ramirez,Renata T Souza,José F Da Silveira,Eden R Ferreira,Marta M G Teixeira,André G Costa-Martins,Renato A Mortara

doi:10.3390/genes11091085

Werica P Bernardo, José Luis Ramirez + Show 6 more

Open Access

https://doi.org/10.3390/genes11091085

Copy DOI

Abstract

Retrotransposon Hot Spot (RHS) is the most abundant gene family in Trypanosoma cruzi, with unknown function in this parasite. The aim of this work was to shed light on the organization and expression of RHS in T. cruzi. The diversity of the RHS protein family in T. cruzi was demonstrated by phylogenetic and recombination analyses. Transcribed sequences carrying the RHS domain were classified into ten distinct groups of monophyletic origin. We identified numerous recombination events among the RHS and traced the origins of the donors and target sequences. The transcribed RHS genes have a mosaic structure that may contain fragments of different RHS inserted in the target sequence. About 30% of RHS sequences are located in the subtelomere, a region very susceptible to recombination. The evolution of the RHS family has been marked by many events, including gene duplication by unequal mitotic crossing-over, homologous, as well as ectopic recombination, and gene conversion. The expression of RHS was analyzed by immunofluorescence and immunoblotting using anti-RHS antibodies. RHS proteins are evenly distributed in the nuclear region of T. cruzi replicative forms (amastigote and epimastigote), suggesting that they could be involved in the control of the chromatin structure and gene expression, as has been proposed for T. brucei.

Highlights

The flagellate protozoan Trypanosoma cruzi is the etiologic agent of Chagas disease or American trypanosomiasis, which affects 6–7 million people mainly in Latin America, with an increasing number of cases in non-endemic countries such as Canada, the United States of America, and some European countries [1]
We aimed to investigate the structure, evolution, and expression of the Retrotransposon Hot Spot (RHS) multigene family in T. cruzi
The epimastigotes of T. cruzi, T. cruzi marinkellei, and T. rangeli were grown in axenic cultures at 28 ◦ C in liver-infusion tryptose (LIT) medium [15] supplemented with 10–20% heat-inactivated fetal calf serum

Summary

Introduction

The flagellate protozoan Trypanosoma cruzi is the etiologic agent of Chagas disease or American trypanosomiasis, which affects 6–7 million people mainly in Latin America, with an increasing number of cases in non-endemic countries such as Canada, the United States of America, and some European countries [1]. When compared with other members of the genus Trypanosoma, the T. cruzi genome was expanded, being 2.3-fold larger than that of T. brucei and T. rangeli. Repetitive DNA sequences comprise about 52% of the T. cruzi genome [2,3,4]. The dramatic expansion and diversification of repetitive sequences, of multigene family encoding proteins, such as surface proteins (TS (Trans-Sialidase), MASP (Mucin-Associated Surface Protein), mucins, gp, Retrotransposon Hot. Spot (RHS), and DGF-1 (Dispersed Gene Family-1)) may have contributed to the speciation of the. T. cruzi taxon [2,5]. RHS proteins are coded by a multigene family found in the genus Trypanosoma.

Objectives

Methods

Results

Conclusion