Madrid, 8 (European Press)

New research has determined for the first time how hydras, small aquatic animals, can regenerate their heads by changing the way their genes are regulated.

Hydra belongs to the group of fauna consisting of about 10,000 species divided into two large groups: anthozoa (consisting of sea anemones, corals and sea feathers) and Medsozoa (sea wasps, jellyfish and hydra). Hydra, which live in temperate and tropical regions, are believed to be biologically immortal because Hydra stem cells have an unlimited capacity for self-renewal.

Whole body regeneration occurs in a few animal species. The extent to which the genes and genetic regulatory networks that drive regeneration differ from species to species has not been studied. Scientists still do not understand the mechanism that drives the regeneration of the hydra’s head.

Evidence for regulation by multiple developmental pathways has been found in previous studies. Researchers have found several genes associated with head regeneration.

To understand the fundamentals that control hydra head regeneration, the researchers in the new study first identified 27,137 active elements in one or more divisions of the regenerating organism or tissue body.

They used histone ChIP-seq modification, a method used to analyze how proteins interact with DNA, to identify 9,998 candidate regions for proximal promoters and 3018 enhancer candidate regions, respectively.

Their research, published in Genome Biology and Evolution, shows that a subset of these regulatory elements are remodeled during head regeneration and identifies a set of transcription factor isoforms that are enriched in active regions during head regeneration. These enriched forms include developmental transcription factors.

This work identifies for the first time the specific candidate regulatory elements of the genome that change during hydra head regeneration, and that determine how organisms develop by turning genes on or off as needed.

“An exciting finding from this work is that hydra vegetation and head regeneration programs are quite different, highlights the paper’s lead author, Aide Macias-Muñoz.

“Although the result is the same (the hydra head), gene expression is more diverse during regeneration – he adds -. Dynamic gene expression is accompanied by dynamic remodeling of chromatin in places where developmental transcription factors are present. These results suggest that enhancer complexes are Developmentalism existed before the division of Cnidaria and Bilateria.”