Generation of insulin-producing cells by ectopic expression of Ptf1a

The following protocol describes the differentiation of mouse embryonic stem cells into all pancreatic lineages, including acinar, endocrine and ductal cells, by transient activation of the PTF1a gene. Extended cultivation of the embryonic stem cells with retinoic acid and nicotinamide enables the generation of more insulin-producing cells on the expense of other cell lineages. The induced cells express typical markers of endocrine progenitor cells.