Phase transitioned nuclear Oskar promotes cell division of Drosophila primordial germ cells
Abstract
Germ granules are non-membranous ribonucleoprotein granules deemed the hubs for post-transcriptional gene regulation and functionally linked to germ cell fate across species. Little is known about the physical properties of germ granules and how these relate to germ cell function. Here we study two types of germ granules in the Drosophila embryo: cytoplasmic germ granules that instruct primordial germ cells (PGCs) formation and nuclear germ granules within early PGCs with unknown function. We show that cytoplasmic and nuclear germ granules are phase transitioned condensates nucleated by Oskar protein that display liquid as well as hydrogel-like properties. Focusing on nuclear granules, we find that Oskar drives their formation in heterologous cell systems. Multiple, independent Oskar protein domains synergize to promote granule phase separation. Deletion of Oskar's nuclear localization sequence specifically ablates nuclear granules in cell systems. In the embryo, nuclear germ granules promote germ cell divisions thereby increasing PGC number for the next generation.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data has been provided for Figure 3 and Figure 3-figure supplement 1 (Supplementary file 1).
Article and author information
Author details
Funding
Howard Hughes Medical Institute
- Ruth Lehmann
Eunice Kennedy Shriver National Institute of Child Health and Human Development (K99HD088675)
- Tatjana Trcek
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Anthony A Hyman, Max Planck Institute of Molecular Cell Biology and Genetics, Germany
Version history
- Received: April 28, 2018
- Accepted: September 9, 2018
- Accepted Manuscript published: September 27, 2018 (version 1)
- Version of Record published: October 16, 2018 (version 2)
Copyright
© 2018, Kistler et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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