Shp2 deficiency leads to reduced expression and function of Pdx1. (A and B) qRT-PCR analysis of characterized β-cell gene products and cell-cycle regulators in control and Shp2-knockout islets (A) or in control and Shp2-knockdown INS-1 832/13 cells (B). mRNA levels were normalized to cph mRNA. Data are means ± SEM. *, P < 0.05, **, P < 0.01; ***, P <.001. (C) Anti-Pdx-1 ChIP assay performed on Shp2-knockdown and control INS-1 832/13 cells and analyzed by semiquantitative PCR to detect association of Pdx1 with elements in the Ins1 and Ins2 promoters. (D) Quantitative PCR analysis compares association of Pdx1 with promoters of Ins1 and Ins2. (E) (Left) Insulin content (ng/μg of total protein) of INS-1 832/13 cells 72 h after transfection with Shp2-siRNA + empty vector, Shp2-siRNA + Pdx1 cDNA, and scrambled-siRNA + empty vector. (Right) Immunoblot of Flag, Pdx-1, Shp2, and α-tubulin in lysates of these 3 groups of INS-1 832/13 cells.