In silico analysis of trypanosomatids' helicases

Abstract

Trypanosomatids are unicellular protozoan parasites that cause many diseases in animals, including humans, and plants. These early divergent eukaryotes have many singular structures and processes, including the hyper-modified ‘base J’, a mitochondrial DNA network, RNA editing, and trans-splicing; all of these unique features involve a wide variety of specific DNA/RNA helicases. In this work, the genomes of trypanosomatids were analyzed by data mining, searching for genes coding for DNA/RNA helicases. Specific motifs and fulllength sequences from all families present in the helicase’s superfamilies (SFs) 1 and 2 were used as baits for genome analyses. A total of 328 putative helicases were identified; 204 genes were assigned to the SF2, 42 genes to the SF1, and 76 genes remain unclassified. Eight species-specific SF2 helicases were also found; Trypanosoma cruzi has three DEAD-box and one DEAH/RHA-specific helicases, while Leishmania major has three Swi2/Snf2 and Trypanosoma brucei has only one RigI helicase. Finally, to identify helicases that could be used as future therapeutic targets, all obtained genes were compared with those present in the human genome. Forty-two helicases underrepresented in the human genome were identified; constituting 16 orthologs groups from L. major, T. brucei, and T. cruzi.