Dynamic Proteomic Analysis of Pancreatic Mesenchyme Reveals Novel Factors That Enhance Human Embryonic Stem Cell to Pancreatic Cell Differentiation

Figure 1

Isolation of pancreatic mesenchyme for proteomic analysis. (a) Schematic representation of transgenic mouse models employed to permanently label pancreatic mesenchymal cells. The mesenchyme specific Nkx3.2 promoter drives Cre recombinase expression during organogenesis and results in the excision of a loxp site flanked stop sequence. This excision in turn gives rise to constitutive expression of the fluorescence reporter YFP specifically in mesenchymal cells. (b) Representative dot plot of fluorescence activated cell sorting of YFP labeled mesenchymal cells. Approximate numbers of sorted YFP⁺ cells per litter and postpartum mouse are given in the inset. (c) Schematic illustrating the sample preparation and mass spectrometric analysis. (d) Table with total number of identified peptides per time point and corresponding protein discoveries with false discovery rates (FDR) of 5% and 1%, respectively.

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