The Drosophila male Germline stem cell niche
Regenerative tissues such as gut, blood and testis constantly provide short-lived functional cells to replace damaged or lost ones. Throughout adult life, regeneration is obtained by rare populations of tissue-specific stem cells that are capable to yield two types of cells upon division: one that is kept as a stem cell for future use and one that differentiates to replace the lost cells. In a given tissue, the stem cell number, fate and division rate is controlled by signals that emanate from the microenvironment namely, the stem cell niche.
The germline stem cell niche of the Drosophila testis: Four germline stem cells marked with white dots and form physical contact with the hub (blue), a major component of the niche supporting cells. Arrowhead marks spermatogonia 'cyst' (red) of differentiated germ cells. Arrow and bright GFP mark thin elongated cyst cells that encapsulate spermatogonia cysts.
The complexity of mammalian tissues present a big obstacle in tissue regeneration research. Particularly, the lack of specific markers present the unequivocal identification of the rare stem cells and their niche supporting cells. To overcome this problem, we chose the Drosophila testis as the main research model for in the lab for its following benefits: i) Stem and niche cells can be identified at a single-cell resolution and can be genetically manipulated selectively, easily and rapidly. ii) The consistent production of short-lived sperm cells relies on a robust stem cell system, which balances self-renewal with differentiation iii) Lastly, since the testis is not critical for maintaining adult life, genetic manipulations in distinct cells and their contribution to the overall homeostasis phenotype can be studied without destroying the organism.