Zebra fish have unsuspected regenerative powers: they are capable of replacing a heart muscle or an amputated fin with a perfect copy. And what is more, even though there are important differences in the structure of these two organs, the regeneration of their tissue depends on the same gene regulation, which has been demonstrated in a recent study by Professor Anna Jaźwińska and Dr Catherine Pfefferli of the University of Fribourg.

Zebra fish, used as model organisms in biology, can perfectly repair lost tissue after a heart attack or an amputation. And they don’t need “magic” stem cells to do this: they activate still functioning cells on the edge of the wound to enable a new organ to develop. In carrying out their study of this extraordinary regenerative ability, the biologists Anna Jaźwińska and Catherine Pfefferli were able to show that the same genetic base is responsible for the activation of the cells of both the heart and the fin.

Turning back the biological clock
Despite the morphological and functional differences between the two organs, the regenerative cells activate, in effect, an identical genetic element which the two researchers at the University of Fribourg have dubbed careg. The DNA sequence careg enables the cardiomyocytes (cardiac muscle cells) and the dermal fin cells to turn their biological clock back to the developmental phase. At the molecular level, the researchers were able to determine that the activation of careg is stimulated by the growth factor TGF-beta (Transforming Growth Factor beta). The analysis of genetically modified zebra fish has proven that the careg cells are all that is needed to completely regenerate the heart and fin tissue.

The discovery of the source of cell plasticity in these model organisms presents highly promising possibilities for biology and regenerative medicine: it gives us an idea how developmental programs could be reactivated, for example at the level of a wound in human tissue.

• This article appeared in Nature Communication