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Antigenic variation in Babesia bovis occurs through segmental gene conversion of the ves multigene family, within a bidirectional locus of active transcription
Author(s) -
AlKhedery Basima,
Allred David R.
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04993.x
Subject(s) - biology , babesia bovis , gene , locus (genetics) , antigenic variation , genetics , gene conversion , gene family , transcription (linguistics) , epigenetics , allele , gene expression , babesia , virology , linguistics , philosophy
Summary Antigenic variation in Babesia bovis is one aspect of a multifunctional virulence/survival mechanism mediated by the heterodimeric variant erythrocyte surface antigen 1 (VESA1) protein that also involves endothelial cytoadhesion with sequestration of mature parasitized erythrocytes. The ves 1α gene encoding the VESA1a subunit was previously identified. In this study, we present the unique organization of the genomic locus from which ves 1α is transcribed, and identify a novel branch of the ves multigene family, ves 1β. These genes are found together, closely juxtaposed and divergently oriented, at the locus of active transcription. We provide compelling evidence that variation of both transcriptionally active genes occurs through a mechanism of segmental gene conversion involving sequence donor genes of similar organization. These results also suggest the possibility of epigenetic regulation through in situ switching among gene loci, further expanding the potential repertoire of variant proteins.