Prior to ovulation and fertilization, oocytes undergo a prolonged phase of growth within the ovarian follicle, during which they accumulate macromolecules and organelles that will sustain and direct early embryonic development, followed by a brief phase termed meiotic maturation, coincident with ovulation, and during which they complete the first and prepare for the second meiotic division. Growth and maturation of the oocyte are indispensable prerequisites in order to produce a healthy embryo after fertilization. Our lab focuses on three questions:
- How do growing oocytes establish and maintain communication with the neighbouring somatic cells of the ovarian follicle? This communication is essential for normal oocyte development. We have found that factors secreted by the oocyte induce the neighbouring somatic cells to extend filopodia to the oocyte, enabling communication lines to be established. Current work focuses on the molecular mechanism of this filopodial formation and on their fate during meiotic maturation.
- How do growing and maturing oocytes regulate mRNA translation? Many mRNAs synthesize by growing oocytes remain translationally silent until they are activated for translation during meiotic maturation. We are studying the mechanisms by which this translational control is exerted, and whether abnormal regulation of mRNA translational activation may contribute to the poor quality of in vitro-matured oocytes.
- Can healthy oocytes be grown in vitro? There is considerable clinical interest in developing culture systems that support oocyte growth in vitro. Systems developed to date, however, produce a very low yield of healthy oocytes. Using 3-dimensional matrices developed to model tumour growth, we are testing whether these can support the growth and development of healthy oocytes.