Temperature sensitive cdc mutants were crucial at the real beginning of the cell cycle regulation study. Most of the cell cycle regulators are encoded by essential genes; conditional mutants were therefore the only way how to approach them by forward genetics. Multiple fission, e. g. the mechanism used for division by the model organism C. reinhardtii, has been only little understood so far. It is a specific cell cycle resembling both the overlapping cell cycles of bacteria and the early embryonic division of Drosophila melanogaster. Recently, we have prepared temperature sensitive cdc mutants of the green alga C. reinhardtii. The mutants show a wide range of different phenotypes during the cell cycle. The phehotypes could be caused either by a mutation in already known cell cycle regulator or in novel genes or genes specific for multiple fission cell cycle regulation. Both groups of mutants are potentially interested because they offer a better insight into the multiple fission cell cycle regulation. The aim of the project is to characterize one of the cdc mutants. For a PhD project the research will include genetic mapping of the mutation by map based cloning, gene complementation and phenotype characterization by cell biology (light and fluorescent microscopy, cell cycle progression analysis), molecular biology and biochemistry (gene expression analysis, enzymology, Western blotting). For a MSc project only one part of the larger project will be chosen based on the student´s interest (mutation mapping using map based cloning, phenotype analysis).
Wee1 kinase is the key regulator of mitosis. It is responsible for phosphorylation and inactivation of mitotic CDK/cyclin complex. In yeast and mammals, it is important both for the normal cell cycle progression and for the cell cycle block in response to DNA damage. In higher plants, Wee1 kinase has a function in endoreduplication and in DNA damage response; however, it may have no role in the normal cell cycle regulation. Our results show Wee1 kinase of C. reinhardtii regulates both the normal cell cycle progression and the cell cycle block after DNA damage. The aim of the project is to analyze the function of Wee1 kinase in the moss P. patens. The student will prepare and verify recombinant moss strains with Wee1 fused to either GFP or GUS. The Wee1 will be then localized by both light and fluorescent microscopy. The changes in localization and gene expression in response to DNA damage will be also analyzed.
Institute of Microbiology
Academy of Sciences of the Czech Republic