Automated nuclear analysis of Leishmania major telomeric clusters reveals changes in their organization during the parasite's life cycle.
Parasite virulence genes are usually associated with telomeres. The clustering of the telomeres, together with their particular spatial distribution in the nucleus of human parasites such as Plasmodium falciparum and Trypanosoma brucei, has been suggested to play a role in facilitating ectopic recombination and in the emergence of new antigenic variants. Leishmania parasites, as well as other trypanosomes, have unusual gene expression characteristics, such as polycistronic and constitutive transcription of protein-coding genes. Leishmania subtelomeric regions are even more unique because unlike these regions in other trypanosomes they are devoid of virulence genes. Given these peculiarities of Leishmania, we sought to investigate how telomeres are organized in the nucleus of Leishmania major parasites at both the human and insect stages of their life cycle. We developed a new automated and precise method for identifying telomere position in the three-dimensional space of the nucleus, and we found that the telomeres are organized in clusters present in similar numbers in both the human and insect stages. While the number of clusters remained the same, their distribution differed between the two stages. The telomeric clusters were found more concentrated near the center of the nucleus in the human stage than in the insect stage suggesting reorganization during the parasite's differentiation process between the two hosts. These data provide the first 3D analysis of Leishmania telomere organization. The possible biological implications of these findings are discussed.
Systems Biology of Pathogens Group, Institut Pasteur Korea, Seoul, South Korea.
Fernando de M
Fde M
Dossin
Alexandre
A
Dufour
Elodie
E
Dusch
Jair L
JL
Siqueira-Neto
Carolina B
CB
Moraes
Gyong Seon
GS
Yang
Maria Isabel
MI
Cano
Auguste
A
Genovesio
Lucio H
LH
Freitas-Junior
D000818:Animals; D001331:Automation; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D018320:Leishmania major / Q000235:genetics* / Q000254:growth & development*; D008018:Life Cycle Stages; D051379:Mice; D016615:Telomere