Fig. 2

Synergistic action between PDX1 and NKX6.1 regulates C-peptide release. PDX1 functions together with NKX6.1 to initiate insulin transcription (or gene expression) during the differentiation, which results in the generation of functional beta cells. If PDX1 and NKX6.1 levels are high, the transcription of insulin gene will be increased leading to positive expression of MAFA and NEUROD1, thereby generating functional beta cells. On the other hand, reduced PDX1 and NKX6.1 gene levels will result in the decrease of the insulin gene further leading to the downstream generation of mixed or variable cells. The green arrow indicates increased levels of gene expression. The red arrow indicates decreased levels of gene expression. PDX1 duodenal homeobox 1, NKX6.1 NK6 homeobox 1, MAFA MAF BZIP transcription factor A, NEUROD1 neuronal differentiation 1