Morphological Events during the Trypanosoma cruzi Cell Cycle

Elias, Maria Carolina; Cunha, Júlia Pinheiro Chagas da; Faria, Flávio Paulo de; Mortara, Renato Arruda; Freymüller, Edna; Schenkman, Sérgio

doi:10.1016/j.protis.2006.10.002

Cited by 97 publications

(136 citation statements)

References 30 publications

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“…cruzi epimastigotes in the early G2 phase of the cell cycle, characterized by the presence of one nucleus, one kinetoplast and two flagella (1N1K2F), still possess a single cytostome-cytopharynx complex (Ramos et al, 2011) and, despite a relatively discrete morphological change in shape and length, this complex remains functional, being able to uptake endocytic tracers (Alcantara et al, 2014). Later stages of the cell cycle (mitosis and cytokinesis) are of short duration (Elias et al, 2007), which makes the analysis of cells in these key cell cycle phases difficult in non-synchronized cultures. Therefore, to study the biogenesis of the cytostome-cytopharynx complex during cell division, we arrested cells in the G1 phase of the cell cycle by using hydroxyurea (HU) and analyzed cell populations 10-14 h after release from the HU block, where cells in G2, mitosis and cytokinesis are more abundant (Galanti et al, 1994;Elias et al, 2007).…”

Section: Resultsmentioning

confidence: 99%

“…This pattern is required to faithfully duplicate and segregate a number of single-copy organelles, including the mitochondrion, the kinetoplast (the region of the mitochondrion containing the DNA, known as kDNA), the basal body complex and the flagellum. In T. cruzi epimastigotes the G1 phase of the cell cycle lasts for approximately 10 h, and is followed by an S phase where both mitochondrial (kinetoplast) and nuclear DNA genomes replicate (Elias et al, 2007). In the G2 phase, which lasts ∼8.6 h, the pro-basal body matures and elongates into a new flagellum, which emerges from the flagellar pocket next to the old flagellum, at the anterior region of the cell.…”

Section: Introductionmentioning

confidence: 99%

“…Similar to the cytostomecytopharynx, the flagellar pocket is a specialized cell membrane domain devoid of subpellicular microtubules, but associated with a specialized set of microtubules -the MtQ -which duplicate early in cell division, before probasal body maturation and elongation, in a position anterior to the old MtQ. In T. cruzi, however, comparatively little is known about organelle and cytoskeleton duplication during cell division (Elias et al, 2007;Ramos et al, 2011), and the events involved in the division and segregation of the cytostomecytopharynx complex have not been described. In our previous work (Alcantara et al, 2014), we showed that the cytopharynx of cells in early G2 (i.e.…”

Section: Introductionmentioning

confidence: 99%

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The cytostome-cytopharynx complex ofTrypanosoma cruziepimastigotes disassembles during cell division

Alcantara

Vidal

Souza

et al. 2016

Journal of Cell Science

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The cytostome-cytopharynx complex is the main site for endocytosis in epimastigotes of Trypanosoma cruzi. It consists of an opening at the plasma membrane surface -the cytostome -followed by a membrane invagination -the cytopharynx. In G1/S cells, this structure is associated with two specific sets of microtubules, a quartet and a triplet. Here, we used electron microscopy and electron tomography to build 3D models of the complex at different stages of the cell cycle. The cytostome-cytopharynx is absent in late G2 and M phase cells, whereas early G2 cells have either a short cytopharynx or no visible complex, with numerous vesicles aligned to the cytostome-cytopharynx microtubules. The microtubule quartet remains visible throughout cell division (albeit in a shorter form), and is duplicated during G2/M. In contrast, the microtubule triplet is absent during late G2/M. Cells in cytokinesis have an invagination of the flagellar pocket membrane likely to represent early stages in cytostome-cytopharynx assembly. Cells in late cytokinesis have two fully developed cytostome-cytopharynx complexes. Our data suggest that the microtubule quartet serves as a guide for new cytostome-cytopharynx assembly.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The cytostome-cytopharynx complex ofTrypanosoma cruziepimastigotes disassembles during cell division

Alcantara

Vidal

Souza

et al. 2016

Journal of Cell Science

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“…*p < 0.05. and cells with two nuclei, two kinetoplasts and two flagella (2N2k2F) are in cytokinesis. 16 The cells were stained with mAb25, which labels flagella, DAPI and anti-TcOrc1/Cdc6 ( fig. 5a) or anti-TcPCNA (fig.…”

Section: Resultsmentioning

confidence: 99%

“…Based on previous results regarding morphological patterns of each cell cycle stage of T. cruzi replicative forms, 16 we established the dynamics of TcOrc1/ Cdc6 and TcPCNA, pre-replication and replication machinery components, respectively. After division, cells enter into the G 1 phase and TcOrc1/Cdc6 and TcPCNA are dispersed throughout the nuclear space, excluding the nucleolus region.…”

Section: Discussionmentioning

confidence: 99%

Trypanosoma cruziDNA replication includes the sequential recruitment of pre-replication and replication machineries close to nuclear periphery

Calderano¹,

Godoy²,

Motta³

et al. 2011

Nucleus

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Trypanosomatid Cell Division Kinases

Benz

Thomas

Hammarton

2013

Protein Phosphorylation in Parasites

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Advances have been made recently in understanding the order of events in the cell division cycles of Leishmania spp. and Trypanosoma cruzi, adding to previous knowledge of events in Trypanosoma brucei, and highlighting similarities and differences between these trypanosomatids. However, the present understanding of how the cell cycle is regulated by kinases still largely derives from analyses in T. brucei, since convenient genetic tools for analyzing the function of essential regulators -for example, inducible expression systems and/or RNA interferenceare still lacking in Leishmania and T. cruzi. While current understanding of the function of some kinases (e.g., some cyclin-dependent kinases, the NDR kinases, aurora, tousled-like and polo-like kinases) is now very good, many more remain to be characterized, as do details of the signal transduction pathways in which they operate. A number of protein kinases have, in recent years, been genetically -and in some cases also chemically -validated as potential novel drug targets for human African trypanosomiasis or leishmaniasis, although only a few, including CRK3: CYC6, CRK3:CYCA, the NDR kinases, PK50 and PK53 and polo-like kinase, have been subjected to high-throughput screening to identify small-molecule inhibitors. However, problems with these screens include a failure to identify potent inhibitors against the parasite enzyme in vitro, a lack of selectivity for the parasite enzyme over the equivalent human enzyme, or poor efficacy against the parasite. Thus, further chemical investigations will be required to generate new compounds with more ideal properties.

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Morphological Events during the Trypanosoma cruzi Cell Cycle

Cited by 97 publications

References 30 publications

The cytostome-cytopharynx complex ofTrypanosoma cruziepimastigotes disassembles during cell division

The cytostome-cytopharynx complex ofTrypanosoma cruziepimastigotes disassembles during cell division

Trypanosoma cruziDNA replication includes the sequential recruitment of pre-replication and replication machineries close to nuclear periphery

Trypanosomatid Cell Division Kinases

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