Epigenetic marks and the MLL2 protein place egg cells in stasis throughout childhood

‘A protein called MLL2 produces a distinctive pattern of epigenetic marks that are needed for egg cell stasis.’

Using this approach, they found that, as eggs develop, a mark called H3K4me3 spreads throughout the genome. Scientists have already seen the same mark close to the start of active genes in many cells, but the team discovered that its role in egg cells is different. They showed that the MLL2 protein is responsible for this unusual placement of H3K4me3 in egg cells. Without MLL2, most H3K4me3 marks in egg cells are lost and the cells die before getting the chance to form a new life. 




Speaking about the results, first author Dr Courtney Hanna, said: "Our findings show that H3K4me3 is created in two ways. MLL2 can add the H3K4me3 mark without any nearby gene activity while another process, that doesn't use MLL2, places the same mark around active genes. By studying this new mechanism we hope to expand our knowledge of epigenetics in general as well as adding to our understanding of fertility." Lead scientist, Dr Kelsey, said: "We are only beginning to unravel the details of the connection between epigenetics and egg development, a fundamental aspect of biology that may play a part in transmitting information from mother to fetus. Discoveries like this highlight some of the unusual biological processes that take place in these highly important cells."
Source-Eurekalert