Differential Expression of Three Members of the Multidomain Adhesion CCp Family in Babesia bigemina, Babesia bovis and Theileria equi

Reginaldo G Bastos,Carlos E Suarez,Wendell C Johnson,Jacob M Laughery,Massaro W Ueti,Donald P Knowles,Gordon Langsley

doi:10.1371/journal.pone.0067765

Reginaldo G Bastos, Carlos E Suarez + Show 5 more

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https://doi.org/10.1371/journal.pone.0067765

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Abstract

Members of the CCp protein family have been previously described to be expressed on gametocytes of apicomplexan Plasmodium parasites. Knocking out Plasmodium CCp genes blocks the development of the parasite in the mosquito vector, making the CCp proteins potential targets for the development of a transmission-blocking vaccine. Apicomplexans Babesia bovis and Babesia bigemina are the causative agents of bovine babesiosis, and apicomplexan Theileria equi causes equine piroplasmosis. Bovine babesiosis and equine piroplasmosis are the most economically important parasite diseases that affect worldwide cattle and equine industries, respectively. The recent sequencing of the B. bovis and T. equi genomes has provided the opportunity to identify novel genes involved in parasite biology. Here we characterize three members of the CCp family, named CCp1, CCp2 and CCp3, in B. bigemina, B. bovis and T. equi. Using B. bigemina as an in vitro model, expression of all three CCp genes and proteins was demonstrated in temperature-induced sexual stages. Transcripts for all three CCp genes were found in vivo in blood stages of T. equi, and transcripts for CCp3 were detected in vivo in blood stages of B. bovis. However, no protein expression was detected in T. equi blood stages or B. bovis blood stages or B. bovis tick stages. Collectively, the data demonstrated a differential pattern of expression of three orthologous genes of the multidomain adhesion CCp family by B. bigemina, B. bovis and T. equi. The novel CCp members represent potential targets for innovative approaches to control bovine babesiosis and equine piroplasmosis.

Highlights

Arthropod-borne protozoan parasites of the phylum Apicomplexa cause major diseases in humans and animals, including malaria, babesiosis, and theileriosis [1,2,3]
It is noteworthy that the amino acid identity and similarity was distributed throughout the length of the CCp proteins of B. bovis, T. equi and Plasmodium spp. (Figure S2, Figure S3 and Figure S4)
The B. bovis and T. equi CCp proteins presented similar domain distribution when compared to orthologous members in other apicomplexan parasites

Summary

Introduction

Arthropod-borne protozoan parasites of the phylum Apicomplexa cause major diseases in humans and animals, including malaria, babesiosis, and theileriosis [1,2,3]. Apicomplexan parasites have complex life cycle including asexual stages in vertebrate hosts and sexual stages in arthropod vectors [4]. A better comprehension of the sexual events is needed to develop improved approaches to control the diseases caused by apicomplexan parasites. The growing number of available apicomplexan genomes has provided the opportunity to identify novel genes implicated in the parasite life cycle. Genome-based approaches have identified a highly conserved family of six multidomain adhesion proteins, termed CCp family, that are exclusively expressed on the surface of Plasmodium gametocytes [5,6]. The CCp family has not been identified in any other protozoan except apicomplexan parasites

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