Stem cell autotomy and niche interaction in different systems

Figure 1 Simple systems of the stem cell/progenitor-niche interaction: isolated erythroblastic island and isolated apical complex from an insect exhibit strong resemblances. A: Erythroblastic island from dissociated rat bone marrow. A corona of erythroblasts (EB) has extensive cell-cell contact with their niche, the central macrophage (MA) (from Bessis et al[93] with kind permission of Springer Verlag, Berlin, Heidelberg); B: Isolated testicular apical complex from Locusta migratoria. Germline stem cells (GSC) surround the apical cell (AC), which represents the niche (besides the peripheral cyst stem cells, which were removed) (From Dorn et al[64]).