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Identification of a Coronin‐Like Protein in Babesia Species
Author(s) -
FIGUEROA JULIO V.,
PRECIGOUT ERIC,
CARCY BERNARD,
GORENFLOT ANDRÉ
Publication year - 2004
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1307.017
Subject(s) - biology , babesia bovis , microbiology and biotechnology , fusion protein , babesia , complementary dna , polyclonal antibodies , peptide sequence , recombinant dna , virology , antibody , biochemistry , genetics , gene
A bstract : The present study was designed to immunochemically identify a coronin‐like protein in Babesia bovis, B. bigemina, B. divergens , and B. canis . A 2‐kbp cDNA insert of B. bovis carried by plasmid BvN9 was sequenced by the dideoxichain‐termination method on both strands. The cDNA insert contained a 1719‐bp long open reading frame coding for a deduced protein sequence of 61.7 kDa. Sequence analysis using the PSI‐BLAST program revealed about 30% protein sequence identity with a coronin‐like protein of Plasmodium falciparum . The encoding sequence of the cDNA insert lacking 70 amino acids at the N‐terminal was subcloned in frame into pGEX 4T‐3 to produce a recombinant glutathione S ‐transferase (GST)‐pBv fusion protein. Polyclonal antibodies prepared in rabbits immunized with the purified GST‐fusion protein recognized a Babesia ‐specific component of approximately 60 kDa by immunoprecipitation with [ 35 S]methionine‐labeled parasites. However, two molecules with relative sizes of 60 and 70 kDa were recognized in Babesia ‐infected erythrocyte extracts by immunobloting analysis. The 70‐kDa component was apparently of host erythrocyte origin. In an indirect fluorescent antibody test, the rabbit serum strongly reacted with the merozoite stage of the four Babesia species, but also, although weakly, with the host erythrocyte. A cosedimentation assay performed with GST‐pBv fusion protein and exogenous actin from rabbit liver showed that the GST‐pBv fusion protein, but not the GST protein, was associated to actin. From these results, we conclude that the protein present in the four Babesia species analyzed here may be considered as a novel coronin‐like, actin‐binding protein.