Reproduction Abstracts

A mature fertile oocyte is the foundation of successful embryo development. This central role in the propagation of the species renders the oocyte a focus for research in fundamental cell biology as well as in clinical research, where understanding oocyte biology provides new insights into the treatment of infertility.

Making a good egg requires many critical processes including dramatic changes in the properties and volume of the cytoplasm, cell-cell interactions, highly regulated cell-cycle progression, establishing and maintaining polarity and the ability to undergo fertilization. All of these processes are designed to provide the necessary maternal cytoplasmic and genomic contributions to the subsequent embryo. Abnormalities in the oocyte cell cycle can lead to the arrest of the oocyte at an immature state or, if the oocyte progresses, the formation of an embryo that contains the wrong number of chromosomes (aneuploidy). The frequency of aneuploidy increases exponentially with maternal age and accounts for much of the reported age-related increase in early embryo loss, miscarriage, infertility and Down’s syndrome.

Successful progression through meiosis is dependent on the correct function of key cell cycle regulators that ensure timely progression through the first and second meiotic divisions. Our research has focussed on understanding the mechanisms of how these meiotic divisions are controlled as well as how they are integrated with oocyte polarity and mitochondrial function. Why these processes go wrong with maternal age and more importantly, whether it is possible to circumvent these issues is key to ensuring the making of a healthy viable oocyte.