Identification of the centromeres of Leishmania major

The protozoan pathogen Leishmania affects millions of people and domesticated animals worldwide. Recently, high rates of asymmetrical chromosome allotments during mitosis were observed, leading to the generation of a constitutive mosaic aneuploidy. This type of genome plasticity may be a genetic strategy applied by this parasite to adapt to distinct host environments. The underlying molecular events remain elusive. Leishmania centromeres and kinetochores most likely play a key role in this process; however, their identification with classical methods has failed. Bioinformatic analysis of the unconventional kinetochore complex recently discovered in Trypanosma brucei (KKTs) led to the identification of a Leishmania KKT gene candidate called LmKKT1. GFP-tagged LmKKT1 displayed ‘kinetochore-like’ dynamics of intranuclear localization throughout the cell cycle. ChIP-Seq analysis clearly identified one major peak binding to LmKKT1 per chromosome. Several of the predicted centromere sequences had previously been shown to provide mitotic stability. Each peak covers a region of 4 ±2 kb in size. No specific sequence feature could be found, but two grossly conserved motifs were found for 14/36 chromosomes; and a higher density of retroposon was observed in 27/36 centromeres. The identification of centromeres and of a kinetochore component of Leishmania chromosomes open avenues to explore their role in mosaic aneuploidy.