“Cyclin expression and cyclin-dependent kinase activity patterns through Trypanosoma cruzi cell cycle”.

POTENZA M, TÉLLEZ-IÑÓN MT.

Rosario, Argentina

Congreso; VIII Congreso Argentino de Protozoología y Enfermedades Parasitarias; 2008

Sociedad Argentina de Protozoologia

Cyclin-dependent kinases, in association with cyclins and other factors control the cell cycle. In Trypanosomatids, cell cycle is under study and several cyclins were characterized functionally in T. brucei. In T. cruzi, we have previously identified three cyclins named TcCyc2, 4 and 5, able to associate to the TcCRK1, involved in G1/S phase (Gómez et al. 2001). In a functional assay, TcCyc2 was able to rescue the growth of Saccharomyces cerevisiae mutants for G1/S cyclins, indicating that TcCyc2 could be involved in the cell progression cycle in the parasite. To study the mitotic cyclins, the TcCycB was selected from the T. cruzi genome annotation, based on its high similarity with T. brucei mitotic cyclin TbCyc6, essential for cell cycle progress. A 25-mer peptide belonging to the TcCyB sequence were designed and synthesized to raise an anti-TcCycB serum. To better define the functionality of these proteins, we assessed the participation of both cyclins studying their presence in differents stages of the cell cycle. Extracts from synchronized and non-synchronized T. cruzi epimastigotes were assayed in immunoprecipitation experiments using the specific TcCyc2 and anti-TcCycB IgGs. Kinase activity and western blots were performed at different times along the cell cycle. In synchronized parasites, different kinase activity patterns according to the stage in the cell cycle were observed depending on the anti-cyclin antibody used. In synchronic parasites, one interesting band was immunoprecipitated and detected by western blot using the anti-TcCyc2 antibody. Further experiments, such as mass spectrometry analysis, will be necessary to identify the proteins or protein complexes immunoprecipitated.