Prague team finds Nematostella gastrula organizer regulatory elements active in chordate embryos
Institute of Molecular Genetics researchers report homology between cnidarian and chordate gastrula organizers, based on transgenesis, signaling tests and transcriptomic comparisons.
On 6 November 2026, Nature Communications published a study from the Laboratory of Transcriptional Regulation at the Institute of Molecular Genetics of the Czech Academy of Sciences in Prague. The group compared the gastrula organizer of the cnidarian Nematostella with the organizer of chordates. In both, these domains direct the initial establishment of embryonic axes nature.com
Nature Communicationsnature.comOpen source ↗. Simona Mikula Mrstakova, Pratyasha Biswas and Rohin Sengupta contributed equally; the corresponding author is Iryna Kozmikova.
Cross-species tests of the organizer
The central question was whether the organizer domains of cnidarians and chordates share a common evolutionary origin. The answer bears on how the chordate body plan arose. To address it, the authors combined trans-species transgenesis, perturbations of signaling pathways, cross-phylum single-cell transcriptomic comparisons and transplantation assays.
The authors report that cis-regulatory elements that recapitulate NvBmp2/4 and NvChordin expression in Nematostella also drive organizer-restricted activity in chordate embryos. Because these elements report the endogenous cnidarian organizer regulatory environment, the authors regard this activity as consistent with chordate organizer gene-regulatory logic.
Smad2/3 signaling in the cnidarian organizer
The second line of evidence concerns signaling. As in chordates, Smad2/3-mediated signaling is active in the Nematostella organizer. According to the authors, it is required for organizer-specific expression of NvBmp2/4 and NvChordin nature.com
Nature Communicationsnature.comOpen source ↗.
Taken together, the data support what the authors call remarkable homology between cnidarian and chordate gastrula organizers. They are also consistent with the idea that the cnidarian–bilaterian ancestor had a blastopore organizer with the potential to generate dorsal–anterior chordate fates.
On this basis, the authors propose a scenario in which asymmetric positioning of the ancestral blastopore organizer and skewed body-axis elongation contributed to the emergence of the chordate body plan. This is a hypothesis built on the experimental results, not a directly demonstrated sequence of events. The work was done on embryos and in comparative transcriptomic analysis.
