ME31B globally represses maternal mRNAs by two distinct mechanisms during the Drosophila maternal-to-zygotic transition
Miranda Wang,
Michael Ly,
Andrew Lugowski,
John D Laver,
Howard D Lipshitz,
Craig A Smibert,
Olivia S Rissland
Affiliations
Miranda Wang
Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Canada
Michael Ly
Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada
Andrew Lugowski
Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Canada
John D Laver
Department of Molecular Genetics, University of Toronto, Toronto, Canada
Howard D Lipshitz
Department of Molecular Genetics, University of Toronto, Toronto, Canada
Craig A Smibert
Department of Molecular Genetics, University of Toronto, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada
Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Canada; Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, United States; RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, United States
In animal embryos, control of development is passed from exclusively maternal gene products to those encoded by the embryonic genome in a process referred to as the maternal-to-zygotic transition (MZT). We show that the RNA-binding protein, ME31B, binds to and represses the expression of thousands of maternal mRNAs during the Drosophila MZT. However, ME31B carries out repression in different ways during different phases of the MZT. Early, it represses translation while, later, its binding leads to mRNA destruction, most likely as a consequence of translational repression in the context of robust mRNA decay. In a process dependent on the PNG kinase, levels of ME31B and its partners, Cup and Trailer Hitch (TRAL), decrease by over 10-fold during the MZT, leading to a change in the composition of mRNA–protein complexes. We propose that ME31B is a global repressor whose regulatory impact changes based on its biological context.
