Gene‐expression analysis of early‐ and late‐maturation‐stage rat enamel organ

Lacruz RS, Smith CE, Chen Y‐B, Hubbard MJ, Hacia JG, Paine ML. Gene‐expression analysis of early‐ and late‐maturation‐stage rat enamel organ Eur J Oral Sci 2011; 119 (Suppl. 1): 149–157. © 2011 Eur J Oral Sci Enamel maturation is a dynamic process that involves high rates of mineral acquisition, associated fluctuations in extracellular pH, and resorption of extracellular enamel proteins. During maturation, ameloblasts change from having a tall, thin, and highly polarized organization, characteristic of the secretory stage, to having a low columnar and widened morphology in the maturation stage. To identify potential differences in gene expression throughout maturation, we obtained enamel organ epithelial cells derived from the early‐ and late‐maturation stages of rat incisor and analyzed the global gene‐expression profiles at each stage. Sixty‐three candidate genes were identified as having potential roles in the maturation process. Quantitative PCR was used to confirm the results of this genome‐wide analysis in a subset of genes. Transcripts enriched during late maturation ( n = 38) included those associated with lysosomal activity, solute carrier transport, and calcium signaling. Also up‐regulated were transcripts involved in cellular responses to oxidative stress, proton transport, cell death, and the immune system. Transcripts down‐regulated during the late maturation stage ( n = 25) included those with functions related to cell adhesion, cell signaling, and T‐cell activation. These results indicate that ameloblasts undergo widespread molecular changes during the maturation stage of amelogenesis and hence provide a basis for future functional investigations into the mechanistic basis of enamel mineralization.