FUNCTIONAL CHARACTERIZATION OF THE PRDM10-ZN FINGER TRANSCRIPTION FACTOR IN EARLY MAMMALIAN DEVELOPMENT

SUMMARY During embryonic development and lineage specification, a complex set of extracellular signals is integrated on chromatin by Master Transcription Factors (TF) that modify chromatin structure and gene expression. PRDM proteins are TFs, containing a PR-methyltransferase domain at their N-terminus and DNA-binding Zn-fingers at their C-terminus. All 17 PRDM family members are well known for their role as master regulator of lineage specification and their deregulated expression is often linked to diseases. Our group has characterized the function of PRDM10, a transcriptional activator, orchestrating mouse preimplantation development. Our preliminary data indicate that: 1) Prdm10 zygotic KO embryos have visible defects at embryonic day E3.5; 2) Prdm10 maternal (Zona Pellucida3 (Zp3)-CRE) KO embryos arrest at the zygote/two-cell stage; 3) PRDM10 is unique among PRDM family members, as it contains a Glutamine-rich coactivator domain at its C-terminus. Based on this preliminary data we propose the following experiments: In Aim1 we will determine the function of maternal PRDM10. We will take advantage of the Zp3-CRE strain, to delete Prdm10 in the oocyte, and deplete the PRDM10 maternal protein contribution in the zygote. This will allow us to study the function of PRDM10 before zygotic transcriptional activation and determine the gene network directly regulated by PRDM10. In Aim2 we will determine the mechanism of action of PRDM10 as a transcription factor. In this aim we will characterize the mode of action of PRDM10 (i.e. its methyltransferase activity, its protein interactome, and its transcriptional activation and DNA binding-properties). We will also specifically address PRDM10’s function in dictating the choice of alternative promoter usage. Finally, we will validate the function in oocyte and early embryogenesis of key PRDM10-downstream effectors. The significance of these studies is that Prdm10 is an uncharacterized maternal effect gene, and knowledge of the pathways regulated by this Zn-finger TF will be useful to the field of stem cell biology and reproductive medicine.