Coloured scanning electron micrograph of a fruit fly against a black background.

Dying cells in the gut of fruit flies (Drosophila melanogaster) signal for their own replacement. Credit: DENNIS KUNKEL MICROSCOPY/SPL

Cell biology

Cells in limbo rouse allies before they perish

Dying cells can revive for long enough to trigger their own replacement.

Zombies are a staple of apocalyptic movies, but not all the living dead are evil. In the guts of fruit flies, dying cells revive for a very short time to help other cells to grow.

Cell death is part of natural cell turnover, especially for blood, skin and the lining of the gut. Working in fruit flies (Drosophila melanogaster), Andreas Bergmann at the University of Massachusetts Medical School in Worcester and his colleagues found that, in the insect’s gut, cells that are destined to die can briefly enter an undead-like state that prompts intestinal stem cells to proliferate.

To do so, the dying cells express a protein that binds to the cell’s membrane, stimulating the production of potentially harmful molecules called reactive oxygen species. This prompts the insect’s immune cells to travel to the tissue and produce molecular messengers that tell ‘undead’ cells to activate a protein that signals neighbouring stem cells to multiply.

Transiently ‘undead’ cells could be important for tissue renewal in other organisms, including people, the researchers say.