Gap junctions and the regulation of cellular functions of stem cells during development and differentiation

In multicellular organisms, the role of gap junction intercellular communic ation (GJIC) in the regulation of cell proliferation, cell differentiation, and apoptosis is becoming increasingly recognized as one of the major cell ular functions from the start of the fertilized egg, through normal develop ment of the embryo and fetus, to the sexual maturation of the adult and ult imately to the maintenance of health of the aging adult. Given that the fun ction of this membrane-associated protein channel is to synchronize electro tonic or metabolic functions, differential regulation of function at the tr anscriptional, translational, and posttranslational levels of a family of h ighly evolutionarily conserved genes (connexins) needs to be considered. Bo th inherited mutations and environmental modulation of GJIC could, in princ iple, affect the function of gap junctions to control cell proliferation, c ell differentiation, and apoptosis, thereby leading to a wile variety of pa thologies. We review a few techniques used to characterize the ability of s tem and progenitor cells to perform GJIC. 2000 Academic Press.