Investigating the role of stem cells in tissue homeostasis and organogenesis​​


The adult Drosophila midgut

A model of human intestinal stem cells and their progeny.
Drosophila Image Award 2007
The adult Drosophila midgut, like the vertebrate intestine, is made up of enterocytes (digestive cells) and hormone producing enteroendocrine cells. Previously stem cells had not been described in flies and Drosophila intestinal cells had thought to be relatively stable.

​​An eight-cell intestinal stem cell clone made up of a single stem cell (asterisk), recent stem cell daughter (adjacent to the stem cell), two enteroendocrine cells (arrowheads), and one early enterocyte and three mature enterocytes (larger nuclei). Clone (green), cell membranes (red), enteroendocrine cells (nuclear, red), nucleus (blue).​
This clone and ones like it, demonstrate for the first time the existence of multipotent intestinal stem cells in Drosophila. The ability to easily identify stem cells and to manipulate them genetically will facilitate the analysis of normal and abnormal intestinal function in both Drosophila and vertebrates .

Benjamin Ohlstein and Allan Spradling. 
The adult Drosophila posterior midgut is maintained by pluripotent stem cells. 
Nature, vol, 439, 470-473 (2006).
Recently published
Lucchetta and Ohlstein describe an unexpected mechanism of stem cell replacement in the Drosophila intestine.
They found that in some situations where many stem cells are lost, they can be replaced through a process of ploidy reduction, or amitosis, of differentiated polyploid cells to regenerate functional stem cells.​​​