Pancreas specification: a budding question.

Much recent investigation has been carried out into the mechanisms by which the pancreas is specified from the early endoderm. Recent advances have highlighted important roles for retinoic acid and bone morphogenetic protein signalling in patterning the endoderm at late gastrulation. Subsequently, interactions with the endothelium of the aorta in the dorsal pancreas domain and lateral plate mesoderm in the ventral pancreas domain are the source of essential pancreas-inductive signals. Additionally, the transcription factor Ptf1a has been demonstrated to have a previously unappreciated role in distinguishing pancreas from surrounding duodenal fates.