The intestinal stem cell niche studied through conditional transgenesis

Despite a wealth of experimental data, the precise mechanisms governing the maintenance and regeneration of the intestine remain relatively poorly elucidated. After physical or genetic injury, stem cells from the intestinal crypt are killed and the subsequent repopulation process recruits new stem cells from sources currently unknown. Understanding the genetic elements that determine stein cell fate and the basis by which repopulation occurs will greatly aid our understanding of both stem cell plasticity and the contribution made by the stem cell compartment to malignant disease. It would also provide a better platform to develop therapies to regenerate damaged intestinal epithelia as seen after radiation injuries or inflammatory bowel disease such as Crohn's disease. In this review we discuss some of the basic mechanisms that regulate intestinal stem cell viability and maintenance, and also summarise recent data from our laboratory on the requirement for the Writ pathway in these processes.