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A putative homologue of CDC20/CDH1 in the malaria parasite is essential for male gamete development.

Guttery DS, Ferguson DJ, Poulin B, Xu Z, Straschil U, Klop O, Solyakov L, Sandrini SM, Brady D, Nieduszynski CA, Janse CJ, Holder AA, Tobin AB, Tewari R - PLoS Pathog. (2012)

Bottom Line: Furthermore, qRT-PCR analysis in parasite lines with deletions of two kinase genes involved in male sexual development (map2 and cdpk4), showed a significant increase in cdc20 transcription in activated gametocytes.Changes in global protein phosphorylation patterns in the Δcdc20 mutant parasites were largely different from those observed in the Δmap2 mutant.This suggests that CDC20 and MAP2 are both likely to play independent but vital roles in male gametogenesis.

View Article: PubMed Central - PubMed

Affiliation: Centre for Genetics and Genomics, School of Biology Queens Medical Centre, University of Nottingham, Nottingham, UK.

ABSTRACT
Cell-cycle progression is governed by a series of essential regulatory proteins. Two major regulators are cell-division cycle protein 20 (CDC20) and its homologue, CDC20 homologue 1 (CDH1), which activate the anaphase-promoting complex/cyclosome (APC/C) in mitosis, and facilitate degradation of mitotic APC/C substrates. The malaria parasite, Plasmodium, is a haploid organism which, during its life-cycle undergoes two stages of mitosis; one associated with asexual multiplication and the other with male gametogenesis. Cell-cycle regulation and DNA replication in Plasmodium was recently shown to be dependent on the activity of a number of protein kinases. However, the function of cell division cycle proteins that are also involved in this process, such as CDC20 and CDH1 is totally unknown. Here we examine the role of a putative CDC20/CDH1 in the rodent malaria Plasmodium berghei (Pb) using reverse genetics. Phylogenetic analysis identified a single putative Plasmodium CDC20/CDH1 homologue (termed CDC20 for simplicity) suggesting that Plasmodium APC/C has only one regulator. In our genetic approach to delete the endogenous cdc20 gene of P. berghei, we demonstrate that PbCDC20 plays a vital role in male gametogenesis, but is not essential for mitosis in the asexual blood stage. Furthermore, qRT-PCR analysis in parasite lines with deletions of two kinase genes involved in male sexual development (map2 and cdpk4), showed a significant increase in cdc20 transcription in activated gametocytes. DNA replication and ultra structural analyses of cdc20 and map2 mutants showed similar blockage of nuclear division at the nuclear spindle/kinetochore stage. CDC20 was phosphorylated in asexual and sexual stages, but the level of modification was higher in activated gametocytes and ookinetes. Changes in global protein phosphorylation patterns in the Δcdc20 mutant parasites were largely different from those observed in the Δmap2 mutant. This suggests that CDC20 and MAP2 are both likely to play independent but vital roles in male gametogenesis.

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Related in: MedlinePlus

Summary of phenotypes in mutants of cdpk4, map2 and cdc20.Cdpk4 mutants have been shown to arrest DNA synthesis after activation, whereas cdc20 mutants show a similar phenotype to map2 mutants.
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ppat-1002554-g008: Summary of phenotypes in mutants of cdpk4, map2 and cdc20.Cdpk4 mutants have been shown to arrest DNA synthesis after activation, whereas cdc20 mutants show a similar phenotype to map2 mutants.

Mentions: Functional studies in human systems have shown that a deficiency of CDH1 results in delayed mitotic exit as well as an accumulation of mitotic errors and difficulty in completion of cytokinesis [52], [53], similar to what is observed in our cdc20 and map2 mutants. Therefore we suggest that CDC20 in Plasmodium fulfils the function of both CDC20 and CDH1. Moreover, loss of cdc20 results in arrest during metaphase to anaphase transition [12], [54], [55], with sister chromatids failing to form. How the single CDC20 protein may fulfil the roles of both CDC20 and CDH1 requires further investigation. Our ultrastructure studies for both Δcdc20 and Δmap2 lines, reported for the first time to our knowledge; show that these mutants have a similar arrest in cytokinesis and karyokinesis detected by EM, with defects in nuclear spindle/kinetochore movement and chromatin condensation, confirming our initial light microscopy observation of Δmap2. Unlike the Δmap2 line, we never observed any exflagellation in the Δcdc20 line. As suggested before [56], classical spindle checkpoints are not present in Plasmodium since blockage of microtubule organisation does not appear to block DNA synthesis. Therefore, MAP2 and CDC20 may be involved in a critical cell cycle checkpoint during microgametogenesis that controls DNA replication and mitosis, prior to karyokinesis and cytokinesis and is summarised in Figure 8.


A putative homologue of CDC20/CDH1 in the malaria parasite is essential for male gamete development.

Guttery DS, Ferguson DJ, Poulin B, Xu Z, Straschil U, Klop O, Solyakov L, Sandrini SM, Brady D, Nieduszynski CA, Janse CJ, Holder AA, Tobin AB, Tewari R - PLoS Pathog. (2012)

Summary of phenotypes in mutants of cdpk4, map2 and cdc20.Cdpk4 mutants have been shown to arrest DNA synthesis after activation, whereas cdc20 mutants show a similar phenotype to map2 mutants.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285604&req=5

ppat-1002554-g008: Summary of phenotypes in mutants of cdpk4, map2 and cdc20.Cdpk4 mutants have been shown to arrest DNA synthesis after activation, whereas cdc20 mutants show a similar phenotype to map2 mutants.
Mentions: Functional studies in human systems have shown that a deficiency of CDH1 results in delayed mitotic exit as well as an accumulation of mitotic errors and difficulty in completion of cytokinesis [52], [53], similar to what is observed in our cdc20 and map2 mutants. Therefore we suggest that CDC20 in Plasmodium fulfils the function of both CDC20 and CDH1. Moreover, loss of cdc20 results in arrest during metaphase to anaphase transition [12], [54], [55], with sister chromatids failing to form. How the single CDC20 protein may fulfil the roles of both CDC20 and CDH1 requires further investigation. Our ultrastructure studies for both Δcdc20 and Δmap2 lines, reported for the first time to our knowledge; show that these mutants have a similar arrest in cytokinesis and karyokinesis detected by EM, with defects in nuclear spindle/kinetochore movement and chromatin condensation, confirming our initial light microscopy observation of Δmap2. Unlike the Δmap2 line, we never observed any exflagellation in the Δcdc20 line. As suggested before [56], classical spindle checkpoints are not present in Plasmodium since blockage of microtubule organisation does not appear to block DNA synthesis. Therefore, MAP2 and CDC20 may be involved in a critical cell cycle checkpoint during microgametogenesis that controls DNA replication and mitosis, prior to karyokinesis and cytokinesis and is summarised in Figure 8.

Bottom Line: Furthermore, qRT-PCR analysis in parasite lines with deletions of two kinase genes involved in male sexual development (map2 and cdpk4), showed a significant increase in cdc20 transcription in activated gametocytes.Changes in global protein phosphorylation patterns in the Δcdc20 mutant parasites were largely different from those observed in the Δmap2 mutant.This suggests that CDC20 and MAP2 are both likely to play independent but vital roles in male gametogenesis.

View Article: PubMed Central - PubMed

Affiliation: Centre for Genetics and Genomics, School of Biology Queens Medical Centre, University of Nottingham, Nottingham, UK.

ABSTRACT
Cell-cycle progression is governed by a series of essential regulatory proteins. Two major regulators are cell-division cycle protein 20 (CDC20) and its homologue, CDC20 homologue 1 (CDH1), which activate the anaphase-promoting complex/cyclosome (APC/C) in mitosis, and facilitate degradation of mitotic APC/C substrates. The malaria parasite, Plasmodium, is a haploid organism which, during its life-cycle undergoes two stages of mitosis; one associated with asexual multiplication and the other with male gametogenesis. Cell-cycle regulation and DNA replication in Plasmodium was recently shown to be dependent on the activity of a number of protein kinases. However, the function of cell division cycle proteins that are also involved in this process, such as CDC20 and CDH1 is totally unknown. Here we examine the role of a putative CDC20/CDH1 in the rodent malaria Plasmodium berghei (Pb) using reverse genetics. Phylogenetic analysis identified a single putative Plasmodium CDC20/CDH1 homologue (termed CDC20 for simplicity) suggesting that Plasmodium APC/C has only one regulator. In our genetic approach to delete the endogenous cdc20 gene of P. berghei, we demonstrate that PbCDC20 plays a vital role in male gametogenesis, but is not essential for mitosis in the asexual blood stage. Furthermore, qRT-PCR analysis in parasite lines with deletions of two kinase genes involved in male sexual development (map2 and cdpk4), showed a significant increase in cdc20 transcription in activated gametocytes. DNA replication and ultra structural analyses of cdc20 and map2 mutants showed similar blockage of nuclear division at the nuclear spindle/kinetochore stage. CDC20 was phosphorylated in asexual and sexual stages, but the level of modification was higher in activated gametocytes and ookinetes. Changes in global protein phosphorylation patterns in the Δcdc20 mutant parasites were largely different from those observed in the Δmap2 mutant. This suggests that CDC20 and MAP2 are both likely to play independent but vital roles in male gametogenesis.

Show MeSH
Related in: MedlinePlus