title: Amelogenin sequence and enamel biomineralization in Rana pipiens.
abstract: The amelogenin gene contributes the majority of tooth enamel proteins and plays a significant role in enamel biomineralization. While several mammalian and reptilian amelogenins have been cloned and sequenced, basal vertebrate amelogenin evolution remains to be understood. In order to start elucidating the structure and function of amelogenins in the evolution of enamel, the leopard frog (Rana pipiens) was used as a model. Tissues from Rana pipiens teeth were analyzed for enamel structure and RNA extracts were processed for sequence analysis. Electron microscopy revealed that Rana pipiens enamel contains long and parallel crystals similar to mammalian enamel, while immunoreactions confirmed the site-specific localization of cross-reactive amelogenins in Rana pipiens enamel. Sequencing of amelogenin PCR products revealed a 782bp cDNA with a 546-nucleotide coding sequence encoding 181 amino acids. The homology of the newly discovered Rana pipiens amelogenin nucleotide and amino acid sequence with the published mouse amelogenin was 38.6% and 45%, respectively. These findings report the first complete amelogenin cDNA sequence in amphibians and indicate a close homology between mammalian enamel formation and Rana pipiens enamel biomineralization.
authors.affiliation: Department of Oral Biology and Allan G. Brodie Laboratory for Craniofacial Genetics, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Xinping
authors.initials: X
authors.lastname: Wang
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Xianghong
authors.initials: X
authors.lastname: Luan
authors.forename: Akira
authors.initials: A
authors.lastname: Yamane
authors.forename: Thomas G H
authors.initials: TG
authors.lastname: Diekwisch
mesh_terms: D053523:Amelogenin; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers; D003743:Dental Enamel / Q000378:metabolism* / Q000648:ultrastructure; D003746:Dental Enamel Proteins / Q000235:genetics*; D040461:Gene Components; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010802:Phylogeny; D012313:RNA / Q000235:genetics*; D011894:Rana pipiens / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014070:Tooth / Q000378:metabolism* / Q000502:physiology; D014074:Tooth Calcification / Q000502:physiology*
chemical_list: D053523:Amelogenin; C507200:Amelx protein, mouse; D017931:DNA Primers; D003746:Dental Enamel Proteins; D012313:RNA