Functional consequences of disrupting RNA-binding protein function for oogenesis and oocyte-to- embryo transition.

Tight control of gene expression is critical to life and is achieved by a combination of transcriptional and post-transcriptional regulatory mechanisms. However during certain stages of gametogenesis and post-fertilisation development, transcription is essentially inactive meaning that gene expression is controlled exclusively by post-transcriptional mechanisms. This involves the activation, repression or destruction of pre-existing mRNAs in the cytoplasm by RNA-binding proteins. Recent studies have revealed that mammals encode over 1000 functional RNA-binding proteins but despite critical links between this large class of proteins and a wide range of diseases including reproductive, metabolic, neurological and oncogenic disorders, information on their functions is only available for a handful of RNA-binding protein families. These include the DAZ family of which DAZL is the best studied and is required for male and female gametogenesis in a variety of model organisms (reviewed in PMID: 19225045) and also has an additional role in the oocyte to embryo transition in mammals (PMID: 21460039).

Here we aim to explore the functional consequences of DAZL mutations identified in human patients with reduced fertility (ovarian insufficiency, defective spermatogenesis) on the regulation of mRNAs required for meiosis and the transition to mitosis. Our preliminary data leads us to believe that these mutations may be causative and the first aim of this project is to extend these data into mouse oocytes and embryos to determine whether they are sufficient to disrupt oogenesis and oocyte-to-embryo transition. The second aim is to understand how different mutations in DAZL disrupt its different functions in regulating mRNAs (PMID: 16278232, 16001084, 17526644, unpublished) focusing on its interactions with other key RNA-binding protein families. This project will involve a wide variety of molecular biology techniques and advanced Assisted Reproductive Technologies (e.g. isolation, in vitro maturation and in vitro fertilisation of mouse oocytes, and micromanipulation etc.).