Leishmania amazonensis promastigotes present two distinct modes of nucleus and kinetoplast segregation during cell cycle

PLoS One. 2013 Nov 21;8(11):e81397. doi: 10.1371/journal.pone.0081397. eCollection 2013.

Abstract

Here, we show the morphological events associated with organelle segregation and their timing in the cell cycle of a reference strain of Leishmania (L.) amazonensis promastigotes, the main causative agent of Tegumentary leishmaniasis in the Americas. We show evidences that during the cell cycle, L. amazonensis promastigotes present two distinct modes of nucleus and kinetoplast segregation, which occur in different temporal order in different proportions of cells. We used DAPI-staining and EdU-labeling to monitor the segregation of DNA-containing organelles and DNA replication in wild-type parasites. The emergence of a new flagellum was observed using a specific monoclonal antibody. The results show that L. amazonensis cell cycle division is peculiar, with 65% of the dividing cells duplicating the kinetoplast before the nucleus, and the remaining 35% doing the opposite or duplicating both organelles concomitantly. In both cases, the new flagellum appeared during S to G2 phase in 1N1K cells and thus before the segregation of both DNA-containing organelles; however, we could not determine the exact timing of flagellar synthesis. Most of these results were confirmed by the synchronization of parasites using hydroxyurea. Altogether, our data show that during the cell cycle of L. amazonensis promastigotes, similarly to L. donovani, the segregation of nucleus and kinetoplast do not follow a specific order, especially when compared to other trypanosomatids, reinforcing the idea that this characteristic seems to be species-specific and may represent differences in cellular biology among members of the Leishmania genus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle / physiology*
  • Cell Division / physiology
  • Cell Nucleus / physiology*
  • DNA Replication
  • DNA, Kinetoplast / physiology*
  • Leishmania / physiology*

Substances

  • DNA, Kinetoplast

Grants and funding

This work was supported by grants from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, 2012/50263-5) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq,4744252010-0). MSS, AMP receive doctoral and VSN receive post-doctoral fellowships from FAPESP and EJV receive a financial support from CNPq (PDE 202223/2012-4). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.