FBS Colloquia No.179Nuclear Dynamics Group

Higher order chromosomal structure established by meiotic cohesin

Organisms adopting sexual reproduction have acquired a mechanism for exchanging DNA strands between homologous chromosomes (recombination), thereby facilitating the diversity of the gamete genome. At the same time, physical contact with homologous chromosome pairs to be distributed by chiasma formation enables accurate chromosomal segregation and eventually halve the genome and allow it to propagate to gametes. In fact, the formation of aneuploid gametes due to the failure of meiotic recombination and subsequent chromosome segregation defect is one of the major causes of congenital anomalies such as abortion and Down syndrome. It has been suggested that chromosomes in the meiotic prophase form a higher order conformation and that their structure is necessary for performing recombination reactions. However, the molecular mechanism of how the structure is formed is still enigmatic. Therefore, we aim to elucidate the principle of its construction based on the analysis of meiotic cohesin necessary for the formation of the higher-order structure of the chromosome. I would like to introduce and discuss our recent results.