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The Trithorax group protein dMLL3/4 instructs the assembly of the zygotic genome at fertilization
Author(s) -
Prudêncio Pedro,
Guilgur Leonardo G,
Sobral João,
Becker Jörg D,
Martinho Rui Gonçalo,
NavarroCosta Paulo
Publication year - 2018
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201845728
Subject(s) - zygote , biology , human fertilization , genome , genetics , maternal to zygotic transition , evolutionary biology , gene , embryogenesis
The transition from fertilized oocyte to totipotent embryo relies on maternal factors that are synthetized and accumulated during oocyte development. Yet, it is unclear how oocytes regulate the expression of maternal genes within the transcriptional program of oogenesis. Here, we report that the Drosophila Trithorax group protein dMLL 3/4 (also known as Trr) is essential for the transition to embryo fate at fertilization. In the absence of dMLL 3/4, oocytes develop normally but fail to initiate the embryo mitotic divisions after fertilization. This incapability results from defects in paternal genome reprogramming and maternal meiotic completion. The methyltransferase activity of dMLL 3/4 is dispensable for both these processes. We further show that dMLL 3/4 promotes the expression of a functionally coherent gene subset that is required for the initiation of post‐fertilization development. Accordingly, we identify the evolutionarily conserved IDGF 4 glycoprotein (known as oviductin in mammals) as a new oocyte‐to‐embryo transition gene under direct dMLL 3/4 transcriptional control. Based on these observations, we propose that dMLL 3/4 plays an instructive role in the oocyte‐to‐embryo transition that is functionally uncoupled from the requirements of oogenesis.