Abstract
We have used a telomere-associated chromosome fragmentation strategy to induce internal chromosome-specific breakage of Leishmania chromosomes. The integration of telomeric repeats from the kinetoplastid Trypanosoma brucei into defined positions of the Leishmania genome by homologous recombination can induce chromosome breakage accompanied by the deletion of the chromosomal part that is distal to the site of the break. The cloned telomeric DNA at the end of the truncated chromosomes is functional and it can seed the formation of new telomeric repeats. We found that genome ploidy is often altered upon telomere-mediated chromosome fragmentation events resulting in large chromosomal deletions. In most cases diploidy is either preserved, or partial trisomic cells are observed, but interestingly we report here the generation of partial haploid mutants in this diploid organism. Partial haploid Leishmania mutants should facilitate studies on the function of chromosome-assigned genes. We also present several lines of evidence for the presence of sequences involved in chromosome mitotic stability and segregation during cell cycle in this parasitic protozoan. Telomere-directed chromosome fragmentation studies in Leishmania may constitute a useful tool to assay for centromere function.
Highlights
Leishmania is a kinetoplastid protozoan parasite that is endemic in several parts of the world and is responsible for considerable mortality and morbidity
Leishmania Chromosome Fragmentation Vectors—The ability to engineer large chromosomal alterations by gene targeting mediated by homologous recombination in Leishmania cells would be useful for analyzing chromosome function
To generate a defined chromosomal breakage at internal genomic sites, we have constructed a series of chromosome fragmentation vectors that could direct a cloned telomeric DNA to a specific position within the Leishmania genome
Summary
Leishmania is a kinetoplastid protozoan parasite that is endemic in several parts of the world and is responsible for considerable mortality and morbidity. The structure-function and organization of the telomeres are relatively well known in Leishmania [3, 6] the presence of centromere and origins of replication are not yet established in any protozoan parasite. Our studies show that cloned telomeric and subtelomeric repeats of the kinetoplastid protozoan T. brucei are capable of inducing a chromosome-specific breakage and the seeding of new telomeres Using this strategy we have addressed chromosome mitotic stability during cell division in this kinetoplastid parasitic protozoan and have generated large haploid deletions for facilitating functional studies in this diploid organism
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
