SGER: Purification of the Yeast Synaptonemal Complex

During meiosis reciprocal recombination between homologues appears to be required for proper meiosis I segregation of chromosomes. Interference is the crossover-induced inhibition of additional meiotic recombination and was proposed to be helpful in ensuring that crossovers are evenly distributed over the genome. The mechanism of interference is not known, but the synaptonemal complex (SC) has been proposed to be involved in mediating interference. A better understanding of the molecular mechanism of interference might be gained by investigating the structure of the SC. The only known integral component that is found over the entire length of the SC is the ZIP1 protein. This protein may provide a scaffold for other SC proteins that have not yet been identified. Identification of these components is essential for understanding the mechanisms of interference and other aspects of the meiotic pairing process. This Small Grant for Exploratory Research is aimed at constructing several recombinant ZIP1 constructs that will enable the visualization of the SC as well as the affinity purification of the protein complexes contained in this structure. An existing construct will be modified that is fully functional yet contains green fluorescent protein and affinity tags that will enable the rapid isolation of protein complexes that form with the ZIP1 protein. The identity of any ZIP1 associated proteins will be determined by tandem mass spectroscopy. These studies should enable the identification of the genes corresponding to each protein and provide the groundwork for testing their role in SC complex formation, crossover interference, and other aspects of meiotic recombination and pairing.