Saturday, May 14, 2022

Jellyfish’s stinging cells hold clues to biodiversity

Amazing stuff!

"The cnidocytes – or stinging cells – that are characteristic of sea anemones, hydrae, corals and jellyfish ... are also an excellent model for understanding the emergence of new cell types ...
In new research ... showed that these stinging cells evolved by repurposing a neuron inherited from a pre-cnidarian ancestor. ...
“They suggest that co-option of ancestral cell types was an important source for new cell functions during the early evolution of animals.” ...
For nearly a century, it’s been known that cnidocytes developed from a pool of stem cells that also gives rise to neurons (brain cells), but up to now, no one knew how those stem cells decide to make either a neuron or a cnidocyte. ..."

"... This finding is evidence that stinging cells evolved from a specific subtype of neurons and suggests other neuronal subtypes may have been coopted for other novel secretory functions. ..."

From the abstract:
"Cnidocytes (i.e., stinging cells) are an unequivocally novel cell type used by cnidarians (i.e., corals, jellyfish, and their kin) to immobilize prey. Although they are known to share a common evolutionary origin with neurons, the developmental program that promoted the emergence of cnidocyte fate is not known. Using functional genomics in the sea anemone, Nematostella vectensis, we show that cnidocytes develop by suppression of neural fate in a subset of neurons expressing RFamide. We further show that a single regulatory gene, a C2H2-type zinc finger transcription factor (ZNF845), coordinates both the gain of novel (cnidocyte-specific) traits and the inhibition of ancestral (neural) traits during cnidocyte development and that this gene arose by domain shuffling in the stem cnidarian. Thus, we report a mechanism by which a truly novel regulatory gene (ZNF845) promotes the development of a truly novel cell type (cnidocyte) through duplication of an ancestral cell lineage (neuron) and inhibition of its ancestral identity (RFamide)."

Jellyfish’s stinging cells hold clues to biodiversity | Cornell Chronicle




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