Promoter characterization and transcriptional regulation of Ncb5or, a novel reductase necessary for pancreatic β-cell maintenance

Ncb5or is a ubiquitously expressed gene required for β-cell survival in mice. Examination of mouse tissues demonstrated high levels of expression in the pancreas, heart and kidney. A transcription start site was identified 149 bp upstream from the start codon and transient expression analysis in βTC3 cells indicated the presence of a core promoter located within 348 bp upstream of this site. Deletion of Region C (−216/−157) resulted in a significant decrease in promoter activity and specific nucleotides located in a region designated C2 were demonstrated to be critical for complex binding. Deletion of Region D (−60/−33), which contains multiple consensus Sp1 sites, resulted in an additional loss of promoter activity. The data presented here identify and characterize the previously unknown promoter of Ncb5or, a reductase critical for β-cell survival.