Poster Presentation ANZSCDB National Scientific Meeting 2019

Oocyte specific deletion of PRC2 identifies a link between epigenetic programming in the germline and skeletal development in offspring. (#Poster 34)

Heidi Bildsoe 1 2 , Tesha Tsai 1 2 , Ruby Oberin 3 , Lexie Prokopuk 3 , Ellen Jarred 3 , Narelle McGregor 4 , Natalie Sims 4 5 , Stephen Pederson 6 , David Adelson 6 , Patrick Western 2 3
  1. Centre for Reproductive Health, Hudson Institute for Medical Research , Clayton, Victoria, 3168 Australia
  2. Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia 3168
  3. Centre for Reproductive Health, Hudson Insitute for Medical Research, Clayton, Vic, 3168 Australia
  4. St. Vincent’s Institute of Medical Research, Fitzroy, Victoria, Australia 3065
  5. Department of Medicine at St. Vincent’s Hospital, The University of Melbourne, Fitzroy, Victoria, Australia 3065
  6. School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia

Epigenetic information transmitted from parent to offspring is critically important for the interpretation of the DNA during development of the fetus and in adult life, influencing cell specification, developmental processes and normal postnatal life trajectory. EED is an essential component of Polycomb Repressive Complex 2 (PRC2), which establishes the epigenetic modification H3K27me3 in all animals, including humans.  We have recently demonstrated that PRC2 and H3K27me3 regulate epigenetic programming in mouse germ cells, which is important for early embryo development.  Loss of H3K27me3 in the growing oocyte leads to an offspring overgrowth, with increased overall bone mineralization in combination with changes to fat and muscle content pointing to a pivotal role for epigenetic inheritance in skeletogenesis. Similar overgrowth occurs in Weaver syndrome patients who arise from oocytes or sperm carrying de novo germline mutations in EED. These patients exhibit skeletal defects consistent with known functions of PRC2 in bone development. Our initial transcriptional analysis of GV oocytes without EED function demonstrated that 251 were derepressed and upregulated greater than 2-fold, and only 3 transcripts (including EED) were downregulated consistent with the repressive function of H3K27me3.  Within the group of upregulated transcripts, we identified genes related to bone development including Prrx1, Gli2, Gli3, Nfatc1, Sik3 and Hoxd9 and Hoxd13. These results, together with known function of PRC2 in endochondral bone formation strongly indicates that there is a mechanistic link between PRC2-dependent epigenetic programming in the germline and the observed phenotype.  This work will provide greater understanding of the relationship between germline epigenetic programming in relation to maternally inherited EED and PRC2 and its importance in setting the correct developmental trajectory for offspring.