ABSTRACT
Throughout metazoa, germ cells assemble RNA-protein organelles (germ granules). In Drosophila ovaries, perinuclear nuage forms in the nurse cells, while compositionally similar polar granules form in the oocyte. A similar system appears to exist in the distantly related (∼350 million years) wasp Nasonia, with some surprising divergences. Nuage is similarly formed in Nasonia, except that anterior nurse cells accumulate significantly more nuage, in association with high levels of DNA double-strand breaks, suggesting that increased transposon activity anteriorly is silenced by high nuage levels. In the oocyte, the germ plasm forms a single granule that is 40 times larger than a homologous Drosophila polar granule. While conserved germ granule proteins are recruited to the oosome, they show unusual localization: Tudor protein forms a shell encapsulating the embryonic oosome, while small Oskar/Vasa/Aubergine granules coalesce interiorly. Wasp Vasa itself is unusual since it has an alternative splice form that includes a previously unreported nucleoporin-like phenylalanine-glycine repeat domain. Our work is consistent with the high degree of evolutionary plasticity of membraneless organelles, and describes a new experimental model and resources for studying biomolecular condensates.
Footnotes
Author contributions
Conceptualization: J.A.L., A.L.A.; Methodology: K.K., S.J.T., A.K., J.A.L., A.L.A.; Formal analysis: K.K., S.J.T., A.K., R.S., J.A.L., A.L.A.; Investigation: K.K., S.J.T., A.K., R.S., E.A.; Data curation: K.K., S.J.T., A.K., R.S., E.A.; Writing - original draft: K.K., J.A.L., A.L.A.; Writing - review & editing: K.K., S.J.T., A.K., R.S., E.A., J.A.L., A.L.A.; Supervision: J.A.L., A.L.A.; Funding acquisition: J.A.L., A.L.A.
Funding
This study was supported by the National Institute of General Medical Sciences (R01GM129153 to J.A.L. and A.L.A.). This work was partly supported by a grant from the NIH National Institute of General Medical Sciences (P20GM103436). Deposited in PMC for release after 12 months.
Data availability
All relevant data can be found within the article and its supplementary information.
