Structural and Functional Studies of Nuclear Organization, Chromatin and Chromosome Behaviour during Nuclear Division

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We will investigate the role of the AHOP2 gene in the model plant, Arabidopsis thaliana, to decipher how it functions in coordinating chromosome pairing and genetic exchange. We will examine whether AHOP2 undergoes chemical modifications that affect its function, and look for partner proteins that modulate its activities. The ahop2-1 mutant exhibits aberrant meiotic structures and we will strive to characterize the proteins that make up these structures. We also will characterize meiotic chromatin features for comparisons to those of the neighboring cell layer. ***    Chromosome pairing and genetic exchange are essential features of meiosis, the specialized form of nuclear division that uses these processes to ensure a balanced reduction of the chromosome number from diploid to haploid. The haploid meiotic products differentiate to produce the sperm and eggs that can participate in sexual reproduction. Reciprocal genetic exchange must be done precisely. Too little stringency results in inappropriate exchanges; too much stringency leads to inadequate numbers of exchanges; both scenarios lead to the production of genetically imbalanced chromosome sets. ***    Our team will consist of two Principal investigators, one 50%-time Research Associate, 3 graduate students and 6-8 undergraduates. Our research will utilize a broad range of microscopy and imaging, and genetic and molecular techniques to examine the function of AHOP2 in haploid and diploid plants. We also will use biochemical and genomic technologies to describe the chromatin remodeling associated with the transition from the vegetative to the meiotic program. The techniques and related skills we will utilize also are used in clinical, basic and applied research labs, as well as in industry. Students trained in our labs will be able to contribute to the knowledge and technology-driven sectors of the Canadian economy.***     Meiosis is a critical process in the lifecycle of sexually reproducing organisms, and perturbations can lead to reduced fertility and birth defects. While chromosome movements during meiosis have long been documented, the molecular events that control pairing and ensure that exchange is done precisely are not yet fully understood. Our work should help identify molecular components of pairing and exchange and elucidate the role of AHOP2 in these processes. As well, our studies could enhance plant-breeding programs by allowing the stringency of exchange to be modulated to allow introgression of desirable genes into cultivated species from related wild species. ***    As meiosis is a conserved process, knowledge gained in the plants we study not only can contribute to agriculture, but also can contribute to a better understanding of the origins of birth defects in humans. Finally, many meiotic proteins also are essential to genome maintenance and repair; thus our research may lead to a deeper understanding of genome integrity and DNA repair. ********