title: Functional characterization of TcCYC2 cyclin from Trypanosoma cruzi.
abstract: In eukaryotes, an oscillating network of protein kinase activities drives the order and timing of the cell cycle progression. Complexes formed by cyclins associated to cyclin-dependent kinases (CDKs) are the central components of this network. Cyclins act as the activating subunits and their abundance is regulated by different mechanisms in order to promote or prevent kinase activity. Protein synthesis, proteasomal degradation and/or differential subcellular compartmentalization modulate cyclin expression levels along the cell cycle. We describe in this work the characterization of Trypanosoma cruzi Cyclin 2 (TcCYC2), which contributes to a better understanding of the cell cycle regulation in this protozoan parasite. We found TcCYC2 exhibited cyclin function in a yeast complementation assay and over-expression of hemagglutinin tagged TcCYC2-HA rendered shorter duplication times and smaller cell sizes in the epimastigote form of the parasite. Analysis of synchronized cultures showed that over-expression of TcCYC2-HA altered the timing epimastigotes pass through G2/M boundary or cytokinesis. Taken together, our results showed that TcCYC2 is a functional cyclin whose over-expression modifies the dynamics of the cell cycle as well as the morphology of epimastigote forms of T. cruzi, suggesting it plays an important role in the cell cycle regulation machinery.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular Dr. H.N. Torres, INGEBI-CONICET, Vuelta de Obligado 2490, C1428ADN Buenos Aires, Argentina. potenza@dna.uba.ar
authors.forename: Mariana
authors.initials: M
authors.lastname: Potenza
authors.forename: Sergio
authors.initials: S
authors.lastname: Schenkman
authors.forename: Marc
authors.initials: M
authors.lastname: Laverrière
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Tellez-Iñón
mesh_terms: D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000502:physiology*; D016213:Cyclins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D003593:Cytoplasm / Q000737:chemistry; D005434:Flow Cytometry; D015870:Gene Expression; D005816:Genetic Complementation Test; D010802:Phylogeny; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D014162:Transfection; D014349:Trypanosoma cruzi / Q000166:cytology / Q000235:genetics / Q000502:physiology*
chemical_list: D016213:Cyclins; D015800:Protozoan Proteins