Examination of mice containing a Defensin‐5 Cre recombinase transgene

Intestinal epithelium has four differentiated cell types (enterocytes, goblet cells, enteroendocrine cells, and Paneth cells) that arise from a common precursor located near the base of the intestinal crypt. This stem cell gives rise to a population of rapidly dividing cells located just above it. As these cells mature they begin the process of terminal differentiation that ultimately results in a lineage‐specific morphology, function and protein profile. Ongoing research is rapidly identifying differentially expressed proteins within these cell types. Gene targeting of these proteins often results in lethality before the intestinal epithelium is fully developed. Conditional targeting requires mice with an intestinal‐specific Cre recombinase expressing transgene. Currently Cre expressing lines are very limited and there are no available mice that express Cre solely in either goblet or Paneth cells. These studies look at the expression pattern of transgenic mice expressing Cre under the control of the Defensin‐5 promoter. Defensins are a family of small anti‐microbial peptides that are expressed in various epithelia. Defensin‐5 is found within the Paneth cells of the small intestine. Our preliminary goal is to produce a line of mice that express Cre in the Paneth cells and to utilize these mice to examine which molecules play a role in allocation of cells into the Paneth lineage. Supported by NIH # DK052343.