The Experimental Proteome of Leishmania infantum Promastigote and Its Usefulness for Improving Gene Annotations.

África Sanchiz,Sandra González-De La González-De La Fuente,Esther Camacho,Alberto Rastrojo,Esperanza Morato,Jose M Requena,Anabel Marina,Begoña Aguado

doi:10.3390/genes11091036

África Sanchiz, Sandra González-De La González-De La Fuente + Show 6 more

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https://doi.org/10.3390/genes11091036

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Abstract

Leishmania infantum causes visceral leishmaniasis (kala-azar), the most severe form of leishmaniasis, which is lethal if untreated. A few years ago, the re-sequencing and de novo assembling of the L. infantum (JPCM5 strain) genome was accomplished, and now we aimed to describe and characterize the experimental proteome of this species. In this work, we performed a proteomic analysis from axenic cultured promastigotes and carried out a detailed comparison with other Leishmania experimental proteomes published to date. We identified 2352 proteins based on a search of mass spectrometry data against a database built from the six-frame translated genome sequence of L. infantum. We detected many proteins belonging to organelles such as glycosomes, mitochondria, or flagellum, as well as many metabolic enzymes and many putative RNA binding proteins and molecular chaperones. Moreover, we listed some proteins presenting post-translational modifications, such as phosphorylations, acetylations, and methylations. On the other hand, the identification of peptides mapping to genomic regions previously annotated as non-coding allowed for the correction of annotations, leading to the N-terminal extension of protein sequences and the uncovering of eight novel protein-coding genes. The alliance of proteomics, genomics, and transcriptomics has resulted in a powerful combination for improving the annotation of the L. infantum reference genome.

Highlights

The genus Leishmania belongs to the order Trypanosomatida and includes protozoan parasites that are responsible for a complex of diseases named leishmaniasis, which is the second most common cause of mortality among tropical infectious diseases, after malaria [1]
The VL-causative species are genetically almost identical, they differ in geographic distribution: L. donovani is found in the Indian subcontinent and East Africa, while L. infantum is endemic in the countries around the Mediterranean basin, Latin America, and China [2]
L. infantum JPCM5 strain parasites were grown at 26 ◦ C in Roswell Park Memorial Institute (RPMI) 1640 medium supplemented with 15% of heat inactivated fetal calf serum (Biowest SAS, Nuaillé, France)

Summary

Introduction

The genus Leishmania belongs to the order Trypanosomatida and includes protozoan parasites that are responsible for a complex of diseases named leishmaniasis, which is the second most common cause of mortality among tropical infectious diseases, after malaria [1]. Some species of Leishmania are human pathogens that cause different clinical manifestations as cutaneous (CL), mucocutaneous (MCL), or visceral (VL) leishmaniasis. Old World species Leishmania infantum and Leishmania donovani cause VL or kala-azar, which is often lethal if untreated, whereas Leishmania major causes CL and Leishmania braziliensis is associated with MCL. The VL-causative species are genetically almost identical, they differ in geographic distribution: L. donovani is found in the Indian subcontinent and East Africa, while L. infantum is endemic in the countries around the Mediterranean basin, Latin America, and China [2]. Promastigote and amastigote, alternate in the Leishmania life cycle. Promastigotes are flagellated and motile forms develop extracellularly in the gut of their sand-fly

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