Environmental and molecular regulation of asexual reproduction in the sea anemone Nematostella vectensis

Cnidarians exhibit incredible reproductive diversity, with most capable of sexual and asexual reproduction. Here, we investigate factors that influence asexual reproduction in the burrowing sea anemone Nematostella vectensis, which can propagate asexually by transverse fission of the body column. By altering culture conditions, we demonstrate that the presence of a burrowing substrate strongly promotes transverse fission. In addition, we show that animal size does not affect fission rates, and that the plane of fission is fixed along the oral-aboral axis of the polyp. Homeobox transcription factors and components of the TGF beta, Notch, and FGF signalling pathways are differentially expressed in polyps undergoing physal pinching suggesting they are important regulators of transverse fission. Gene ontology analyses further suggest that during transverse fission the cell cycle is suppressed, and that cell adhesion and patterning mechanisms are downregulated to promote separation of the body column. Finally, we demonstrate that the rate of asexual reproduction is sensitive to population density. Collectively, these experiments provide a foundation for mechanistic studies of asexual reproduction in Nematostella, with implications for understanding the reproductive and regenerative biology of other cnidarian species.

Automated summary

We investigate factors influencing asexual reproduction in Nematostella vectensis, a burrowing sea anemone capable of transverse fission. Our study demonstrates that the presence of a burrowing substrate strongly promotes transverse fission and animal size does not affect fission rates. Gene expression analysis suggests that transcription factors and signaling pathways play vital roles in regulating transverse fission. Additionally, we find that the cell cycle is suppressed and cell adhesion and patterning mechanisms are downregulated during fission. This research provides insights into the reproductive biology of cnidarians.