title: Mapping the global mRNA transcriptome during development of the murine first molar.
abstract: The main objective of this study was to map global gene expression in order to provide information about the populations of mRNA species participating in murine tooth development at 24 h intervals, starting at the 11th embryonic day (E11.5) up to the 7th post-natal day (P7). The levels of RNA species expressed during murine tooth development were mesured using a total of 58 deoxyoligonucleotide microarrays. Microarray data was validated using real-time RT-PCR. Differentially expressed genes (p < 0.05) were subjected to bioinformatic analysis to identify cellular activities significantly associated with these genes. Using ANOVA the microarray data yielded 4362 genes as being differentially expressed from the 11th embryonic day (E11.5) up to 7 days post-natal (P7), 1921 of these being genes without known functions. The remaining 2441 genes were subjected to further statistical analysis using a supervised procedure. Bioinformatic analysis results for each time-point studied suggests that the main molecular functions associated with genes expressed at the early pre-natal stages (E12.5-E18.5) were cell cycle progression, cell morphology, lipid metabolism, cellular growth, proliferation, senescence and apoptosis, whereas most genes expressed at post-natal and secretory stages (P0-P7) were significantly associated with regulation of cell migration, biosynthesis, differentiation, oxidative stress, polarization and cell death. Differentially expressed genes (DE) not described earlier during murine tooth development; Inositol 1, 4, 5-triphosphate receptor 3 (Itpr3), metallothionein 1(Mt1), cyclin-dependent kinase 4 (Cdk4), cathepsin D (Ctsd), keratin complex 2, basic, gene 6a (Krt2-6a), cofilin 1, non-muscle (Cfl1), cyclin 2 (Ccnd2), were verified by real-time RT-PCR.
authors: Department of Oral Biology, Faculty of Dentistry, University of Oslo Oslo, Norway.
authors: Maria A
authors: MA
authors: Landin
authors: Bioinformatics Core Facility, Institute for Medical Informatics, Oslo University Hospital and University of Oslo Oslo, Norway.
authors: Ståle
authors: S
authors: Nygård
authors: Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo Oslo, Norway.
authors: Maziar G
authors: MG
authors: Shabestari
authors: The Biotechnology Centre of Oslo, University of Oslo Oslo, Norway.
authors: Eshrat
authors: E
authors: Babaie
authors: Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo Oslo, Norway.
authors: Janne E
authors: JE
authors: Reseland
authors: Department of Oral Biology, Faculty of Dentistry, University of Oslo Oslo, Norway.
authors: Harald
authors: H
authors: Osmundsen
keywords: ITPR3; gene expression; metallothionein 1; microarrays; qPCR; tooth development