Figure 5.
Regulation of pancreatic islet transcription factors. Strong synergistic effects exist in vivo between Pdx-1, Hnf-1α, and Hnf-3β. Hnf-1α and Hnf-3β both regulate the expression of Pdx-1 in vivo and in vitro. Hnf-4α expression is normal in Hnf-4α+/− mutant mice, suggesting an autoregulatory feedback loop. Furthermore, Hnf-4α does not regulate the expression of Hnf-1α or Pdx-1 in pancreatic islets. Gene expression analysis also indicates that Nkx6.1 gene transcript levels are regulated by Pdx-1.
