Correlation between molecular evolution of amelogenin gene and the phenotype of tooth enamel

牙釉质基因分子进化与牙釉质表型的相关性

• 批准号: 14571755
• 负责人: ISHIYAMA Mikio
• 金额: $ 1.09万
• 依托单位: The Nippon Dental University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14571755/
• 关键词: Gene; Amelogenin; Mammals; Molecular evolution Tooth enamel; Phenotype; PCR; PCR; 系統発生

In order to identify and characterize the amelogenin gene in mammals, PCR and RT-PCR were performed by using the genomic DNA (16 species) and cDNA (3 species) in several mammals and some reptiles, with special reference to the correlation with the expression of teeth and the variations of the tooth enamel structure. The specimens used present study were selected to focus on the species which express the unique dental characteristics i.e. edenturous, lacking a tooth enamel and the unique expression of an enamel prisms in non-mammalian species. It is consequently revealed that the exon 6 of amelogenin gene in mammals and reptiles encode 140 amino acids, but only 121 amino acids in porpoise. In the specimens used, however, the PCR products were not obtained in the anteater (Bradypus), jugong (Dugong) and kangaroo (Macropus). As the latter two species possess the teeth with a tooth enamel, the loss of the PCR products were considered to be the less fitting of the primers with the sequences … More of the amelogenin genes. On the other hand, the loss of the products in the edenturous anteater was speculated to be the result of the degeneration of the teeth. Our previous study demonstrated the conservation of the amelogenin gene in edenturous baleen whales, therefore, the degeneration of the teeth in the anteater are estimated to be rather earlier phylogenetically than the degeneration in baleen whales. The present study further demonstrates the presence of the stop codon in the central portion of the exon 6 in the sloth (Bradypus). It is reported that the teeth of the sloth do not have the tooth enamel. The mutation of the exon 6 in the sloth, therefore, might cause the lacking of the tooth enamel. In the agamid lizard Uromaslyx, which uniquely expressess a enamel prism among non-mammalian species, marked insertion of the 24 amino acids (mainly proline) was detected at the central portion of the exon 6. It is, thus, demonstrated that the correlaton between the expression of the unique dental characteristics and the mutations of the amelogenin genes in mammals and reptiles. Less

为了鉴定和表征哺乳动物中的牙釉蛋白基因，利用几种哺乳动物和一些爬行动物的基因组DNA（16种）和cDNA（3种）进行了PCR和RT-PCR，特别是与牙齿表达和牙釉质结构变化的相关性。本研究中使用的标本被选择为重点关注表现出独特牙齿特征的物种，即无牙颌、缺乏牙釉质以及非哺乳动物物种中牙釉质棱柱的独特表现。结果表明，哺乳动物和爬行动物的牙釉蛋白基因外显子6编码140个氨基酸，而海豚仅编码121个氨基酸。然而，在所使用的标本中，食蚁兽 (Bradypus)、儒艮 (Dugong) 和袋鼠 (Macropus) 中未获得 PCR 产物。由于后两个物种拥有带有牙釉质的牙齿，因此 PCR 产物的丢失被认为是引物与釉原蛋白基因序列不太相符。另一方面，无牙食蚁兽中产物的损失被推测是牙齿退化的结果。我们之前的研究证明了无牙须鲸中牙釉蛋白基因的保守性，因此食蚁兽牙齿的退化在系统发育上估计比须鲸的退化要早得多。本研究进一步证明了树懒 (Bradypus) 6 号外显子中央部分存在终止密码子。据悉，树懒的牙齿没有牙釉质。因此，树懒6号外显子的突变可能导致牙釉质缺失。在非哺乳动物物种中独特地表达牙釉质棱柱的蜥蜴Uromaslyx中，在第6外显子的中央部分检测到了24个氨基酸（主要是脯氨酸）的显着插入。因此，证明了哺乳动物和爬行动物中独特牙齿特征的表达与釉原蛋白基因突变之间的相关性。较少的