Stem Cell Biology: Flies As Models and Examples

Drosophila is a genus of flies of the family Drosophilidae. It comprises of 1579 described species. Stem cell present in stem cell niche and interacts to regulate cell fate. Many factors act on embryonic stem cells during embryonic development to alter gene expression, and induce their proliferation or differentiation for the development of the fetus or larvae.

Stem cell niches maintain adult stem cells in a quiescent state. After tissue injury, the surrounding micro-environment induce stem cells to promote either self-renewal or differentiation to new tissues. Various factors are important to coordinate stem cell characteristics within the niche: cell-cell interactions between stem cells, as well as interactions between stem cells and neighbouring differentiated cells, interactions between stem cells and adhesion molecules, extracellular matrix components, the oxygen tension, growth factors, cytokines, and the physicochemical nature of the environment including the pH, ionic strength (e.g. Ca2+ concentration) and metabolites, like ATP, are also important. During development, stem cells and niche may induce each other and alternately maintain each other during adulthood.

Keywords: Germline stem cell, Niche signaling, Niche morphogenesis, Somatic stem cell, siRNA.