Michael Ray

TL;DR: The pdx-1/beta-galactosidase fusion allele is expressed in pancreatic and duodenal cells in the absence of functional PDX-1, with expression continuing into perinatal stages with similar boundaries and expression levels, and offers additional insight into the role of p dx-1 in the determination and differentiation of the posterior foregut.

TL;DR: Rec recombination-based lineage tracing in vivo is used to show that PTF1a is expressed at these early stages in the progenitors of pancreatic ducts, exocrine and endocrine cells, rather than being an exocrine-specific gene as previously described.

TL;DR: Results suggest that HNF3beta, a key regulator of endodermal cell lineage development, plays an essential role in the cell-type-specific transcription of the pdx-1 gene in the pancreas.

TL;DR: Killing Foxl1+ cells by diphtheria toxin administration led to an abrupt cessation of proliferation of both epithelial stem- and transit-amplifying progenitor cell populations that was associated with a loss of active Wnt signaling to the intestinal epithelium, therefore, Foxl 1-expressing mesenchymal cells constitute the fundamental niche for intestinal stem cells.

TL;DR: In vivo evidence is provided of the differential requirements for the level of Pdx1 gene activity in the specification and differentiation of the various organs of the posterior foregut, as well as in pancreas and gut endocrine cell differentiation.