title: Transcriptional factor DLX3 promotes the gene expression of enamel matrix proteins during amelogenesis.
abstract: Mutation of distal-less homeobox 3 (DLX3) is responsible for human tricho-dento-osseous syndrome (TDO) with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP) genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO) inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.
authors: Department of Cariology and Endodontology, School and Hospital of Stomatology, Peking University, Beijing, PR China.
authors: Zhichun
authors: Z
authors: Zhang
authors: Department of Cariology and Endodontology, School and Hospital of Stomatology, Peking University, Beijing, PR China.
authors: Hua
authors: H
authors: Tian
authors: Department of Cariology and Endodontology, School and Hospital of Stomatology, Peking University, Beijing, PR China.
authors: Ping
authors: P
authors: Lv
authors: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, PR China.
authors: Weiping
authors: W
authors: Wang
authors: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, PR China.
authors: Zhuqing
authors: Z
authors: Jia
authors: Department of Cariology and Endodontology, School and Hospital of Stomatology, Peking University, Beijing, PR China.
authors: Sainan
authors: S
authors: Wang
authors: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, PR China.
authors: Chunyan
authors: C
authors: Zhou
authors: Department of Cariology and Endodontology, School and Hospital of Stomatology, Peking University, Beijing, PR China.
authors: Xuejun
authors: X
authors: Gao
mesh_terms: D000565:Ameloblasts / Q000378:metabolism / Q000473:pathology; D000566:Amelogenesis / Q000235:genetics*; D000818:Animals; D019465:Craniofacial Abnormalities / Q000235:genetics* / Q000473:pathology; D003743:Dental Enamel / Q000378:metabolism / Q000473:pathology; D003744:Dental Enamel Hypoplasia / Q000235:genetics* / Q000473:pathology; D018507:Gene Expression Regulation, Developmental; D006201:Hair Diseases / Q000235:genetics* / Q000473:pathology; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics; D014083:Tooth Germ / Q000254:growth & development / Q000378:metabolism*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors