Affinage · Plasmodium

CYC3

PF3D7_0518400 · cyclin, putative

Annotated
2026-09-07
7 papers in source corpus 2 papers cited in narrative 2 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CYC3 (PF3D7_0518400) is the single Plant (P)-type cyclin in Plasmodium and functions in the endomitotic development that drives mosquito-stage sporogony (PMID:26565797). In P. berghei, GFP-tagged CYC3 localizes to both the cytoplasm and nucleus throughout the lifecycle, and deletion of the gene specifically impairs oocyst size, number, and growth, with abnormal budding and defective sporozoite formation, establishing CYC3 as a regulator of endomitotic growth during oocyst maturation (PMID:26565797). Beyond this role in sporogony and a correlative link between CYC3 transcript down-regulation and artemisinin-induced dormancy in P. falciparum (PMID:27326764), no direct cyclin partner, cyclin-dependent kinase, or biochemical activity for CYC3 has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 2 steps
  1. 2015 High

    Whether Plasmodium's sole P-type cyclin had a defined cellular role was unknown; live imaging and gene deletion assigned CYC3 to endomitotic oocyst development, showing which lifecycle stage depends on it.

    Evidence GFP-tagging localization plus reverse-genetics knockout with oocyst phenotyping and stage transcriptomics in P. berghei

    PMID:26565797

    Open questions at the time
    • No CDK or cyclin-binding partner identified for CYC3
    • No biochemical demonstration of cyclin activity or kinase association
    • Mechanism linking CYC3 to budding and sporozoite formation not resolved
  2. 2016 Low

    Whether CYC3 expression tracks with parasite cell-cycle arrest was untested; transcriptional profiling showed pfcyc3 is down-regulated during dormancy and up-regulated on recovery, correlating it with cell-cycle exit and re-entry.

    Evidence Transcription profiling of CDK/cyclin genes before and after DHA treatment across three P. falciparum lines

    PMID:27326764

    Open questions at the time
    • Expression-level correlation only; no functional test of CYC3 protein in dormancy
    • Does not establish whether CYC3 is a driver or a consequence of cell-cycle arrest
    • No P. falciparum knockout to test asexual/dormancy requirement

Open questions

Synthesis pass · forward-looking unresolved questions
  • The molecular mechanism of CYC3 — its partner CDK, substrate specificity, and how it directs endomitotic budding — remains uncharacterized.
  • No identified cyclin-dependent kinase partner
  • No structural model or biochemical reconstitution
  • No mechanistic link between localization and oocyst budding defect

Mechanism profile

Synthesis pass · controlled-vocabulary classification
No controlled-vocabulary terms were assigned to this entry.

Evidence

Reading pass · 2 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2015 CYC3 (PF3D7_0518400), the single Plant (P)-type cyclin in Plasmodium, localizes to both the cytoplasm and nucleus (GFP-tagged protein) throughout the lifecycle in P. berghei. Deletion of cyc3 caused defects in oocyst size, number, and growth, with abnormalities in budding and sporozoite formation, establishing a role for CYC3 in endomitotic development during sporogony. GFP-tagging for subcellular localization; reverse genetics (gene deletion) with phenotypic analysis of oocyst development; global transcript analysis comparing cyc3-deleted vs. wild-type parasites at gametocyte and ookinete stages PLoS pathogens High 26565797
2016 Transcriptional profiling showed that pfcyc3 (PF3D7_0518400) is down-regulated during DHA-induced dormancy in P. falciparum and up-regulated when parasites enter the recovery phase, correlating with cell-cycle arrest and resumption. Transcription profiling of CDK/cyclin genes before and after dihydroartemisinin (DHA) treatment in three P. falciparum parasite lines PloS one Low 27326764

Source papers

Stage 0 corpus · 7 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2015 Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes. PLoS pathogens 49 26565797
2017 The Malaria Parasite Cyclin H Homolog PfCyc1 Is Required for Efficient Cytokinesis in Blood-Stage Plasmodium falciparum. mBio 30 28611247
2016 Correlation between Cyclin Dependent Kinases and Artemisinin-Induced Dormancy in Plasmodium falciparum In Vitro. PloS one 16 27326764
2009 Evolutionary divergence of Plasmodium falciparum: sequences, protein-protein interactions, pathways and processes. Infectious disorders drug targets 8 19519480
2015 Effects of cyclin-dependent kinase inhibitor Purvalanol B application on protein expression and developmental progression in intra-erythrocytic Plasmodium falciparum parasites. Malaria journal 5 25879664
2025 A guide to the apicomplexan cell cycle: endodyogeny and schizogony. Trends in parasitology 2 41173748
2013 In silico characterization and molecular dynamics simulation of Pfcyc-1, a cyclin homolog of Plasmodium falciparum. Journal of biomolecular structure & dynamics 0 23998890