title: Gene-expression analysis of early- and late-maturation-stage rat enamel organ.
abstract: 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.
authors.affiliation: Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA. rodrigo@usc.edu
authors.forename: Rodrigo S
authors.initials: RS
authors.lastname: Lacruz
authors.forename: Charles E
authors.initials: CE
authors.lastname: Smith
authors.forename: Yi-Bu
authors.initials: YB
authors.lastname: Chen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hubbard
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Hacia
authors.forename: Michael L
authors.initials: ML
authors.lastname: Paine
mesh_terms: D000565:Ameloblasts / Q000166:cytology* / Q000378:metabolism; D000566:Amelogenesis / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001692:Biological Transport / Q000235:genetics; D020013:Calcium Signaling / Q000235:genetics; D002448:Cell Adhesion / Q000235:genetics; D004658:Enamel Organ / Q000502:physiology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D055106:Genome-Wide Association Study; D006863:Hydrogen-Ion Concentration; D008213:Lymphocyte Activation / Q000235:genetics; D008247:Lysosomes / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014074:Tooth Calcification / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics; D015854:Up-Regulation