title: Identification of a novel splicing form of amelogenin gene in a reptile, Ctenosaura similis.
abstract: Amelogenin, the major enamel matrix protein in tooth development, has been demonstrated to play a significant role in tooth enamel formation. Previous studies have identified the alternative splicing of amelogenin in many mammalian vertebrates as one mechanism for amelogenin heterogeneous expression in teeth. While amelogenin and its splicing forms in mammalian vertebrates have been cloned and sequenced, the amelogenin gene, especially its splicing forms in non-mammalian species, remains largely unknown. To better understand the mechanism underlying amelogenin evolution, we previously cloned and characterized an amelogenin gene sequence from a squamate, the green iguana. In this study, we employed RT-PCR to amplify the amelogenin gene from the black spiny-tailed iguana Ctenosaura similis teeth, and discovered a novel splicing form of the amelogenin gene. The transcript of the newly identified iguana amelogenin gene (named C. Similis-T2L) is 873 nucleotides long encoding an expected polypeptide of 206 amino acids. The C. Similis-T2L contains a unique exon denominated exon X, which is located between exon 5 and exon 6. The C. Similis-T2L contains 7 exons including exon 1, 2, 3, 5, X, 6, and 7. Analysis of the secondary and tertiary structures of T2L amelogenin protein demonstrated that exon X has a dramatic effect on the amelogenin structures. This is the first report to provide definitive evidence for the amelogenin alternative splicing in non-mammalian vertebrates, revealing a unique exon X and the splicing form of the amelogenin gene transcript in Ctenosaura similis.
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jilin, China. wangxp88@hotmail.com
authors.forename: Xinping
authors.initials: X
authors.lastname: Wang
authors.forename: Xuliang
authors.initials: X
authors.lastname: Deng
authors.forename: Xichen
authors.initials: X
authors.lastname: Zhang
mesh_terms: D053523:Amelogenin / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005091:Exons; D015870:Gene Expression; D007076:Iguanas / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009928:Organ Specificity; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D030162:Reptilian Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014070:Tooth / Q000378:metabolism
chemical_list: D053523:Amelogenin; D017931:DNA Primers; D020033:Protein Isoforms; D030162:Reptilian Proteins