HRMCB · Hidden role of the meiotic chromosomal bouquet

Organisms diversify and propagate their genomes throughout successive generations through the process of meiosis. Understanding the process of meiosis is important, as defects in meiosis are a major cause of miscarriages in humans. In meiotic prophase, telomeres gather near the microtubule organizing-center (MTOC) to form the so-called ‘bouquet’ structure. The extraordinary conservation of the bouquet has suggested that it plays an important role in promoting successful meiosis. My recent work revealed that bouquet formation plays crucial role in regulating the meiotic MTOC and spindle. This discovery raises a number of questions that bear on the relationship between chromosomes and the spindle apparatus.I propose that the chromosomal bouquet is a novel sensor system to monitor progression of meiotic prophase including meiotic recombination, which are required for meiosis I. Completion of these chromosomal events may be signalled from chromosomes to the MTOC to finish bouquet formation. Such chromosome dynamics may be involved in proper formation of the spindle at the later phase, meiosis. I will therefore elucidate how the end of the bouquet is regulated and how such a event affects function of the MOTC using fission yeast as a model organism. Chromosomal components, structure and dynamics in fission yeast are highly conserved among higher eukaryotes. In particular, telomere functions are often reproduced in higher organisms. I will investigate molecular mechanisms using molecular biology and a live cell imaging technique along with yeast genetics. Revealing this communication mechanism will be crucial to our understanding of the meaning of the chromosomal bouquet, and will also provide a fundamental insight into meiosis regulation and chromosome function.