SCI/MIP-1 alpha: a potent stem cell inhibitor with potential roles in development.

The hemopoietic system represents a complex adult developmental system which allows the study of mechanisms of stem cell proliferative control and differentiation commitment. It is likely that information obtained from this model system will have implications for control processes regulating other hierarchical systems in the developing embryo as well as in the adult animal. We have recently identified and isolated a potent inhibitor of hemopoietic stem cell proliferation which we have labeled SCI/MIP-1 alpha. This inhibitor is also active on clonogenic epidermal cells and may thus be a more general stem cell inhibitor than was previously believed. The biology of this peptide is outlined in more detail below and the potential roles for such a factor in the developing embryo are also discussed.