INDUCTION OF PANCREATIC ISLET CELL DIFFERENTIATION BY THE NEUROGENIN-NEUROD CASCADE

Neurog3 and NeuroD1 share the ability to induce endocrine differentiation when expressed ectopically in vivo (Apelqvist et al., 1999; Schwitzgebel et al., 2000; Grapin-Botton et al., 2001) and in vitro (Heremans et al., 2002; Gasa et al., 2004), suggesting that they target a common set of genes. To test this hypothesis, we directly compared in the same cells the effects of Neurog3 and NeuroD1 on global gene expression patterns. Normalized M and A values [limmaGUI output] for the neurogenin3 (Ngn3) and neuroD1 (Nd1) experiments (individual or combined) have been linked below as Supplementary files. Note that M=log2(test/ref), eg, log2(Nd1/Bgal); A=[log2(test*ref)]/2, eg, [log2(Nd1*Bgal)]/2. Additional measures of reliability/probability are also included within the supplementary files. Keywords: comparative genomic hybridization, neurogenin3, neuroD, ductal cells, endocrine, differentiation Mouse pancreatic ductal cells (mPAC cells) were infected with equal titers of recombinant adenoviruses encoding human Neurogenin3 (AdCMV-NEUROG3) or mouse NeuroD1 (AdCMV-NeuroD1), and 48 hrs later their transcriptomes were compared with that of control cells infected with an adenovirus encoding beta­galactosidase (beta-gal; AdCMV-Bgal) using cDNA microarrays. Differences in the activation patterns of the two transcription factors were then determined by comparing the fold-change (FC) values of the pair-wise hybridizations Neurog3/Bgal and NeuroD1/beta-gal.