Phylogenetic distribution and expression of amelogenin genes in vertebrates

为了了解釉原蛋白基因在脊椎动物中的系统发育分布和表达，对7个分类纲的13种脊椎动物进行了Southern杂交、原位杂交和PCR扩增。本研究中使用的种属如下：人、小鼠（哺乳动物）、鸡（鸟类）、凯门鳄、龟、蛇（爬行动物）、蛙（两栖动物）、狗鱼、肺鱼、鳗鱼（硬骨鱼）、角鲨（软骨鱼）和盲鳗、七鳃鳗（无颌）。Southern杂交分析表明，与人cDNA非放射性探针的杂交，获得了所有物种的基因组DNA中使用。这表明这些物种之间的部分DNA序列相似性，并可能表明釉原蛋白基因或釉原蛋白基因样序列在脊椎动物中的普遍分布。然后，我们选择了一条梭子鱼，用人cDNA非放射性探针进行了原位杂交，因为它在梭子鱼中具有重要的生物学意义。 ...更多信息 精细结构和免疫细胞化学分析揭示了釉质发育过程中的遗传位置。Southern杂交检测到与人cDNA探针的杂交，但在牙胚中未检测到mRNA信号。针对人釉原蛋白基因第6外显子的同源序列进行PCR扩增，在人（400 bp）、小鼠（400 bp）、鸡（780 bp）、凯门鳄（400 bp）、龟（750 bp）和蛇（750 bp）的基因组DNA中均得到扩增产物。然而，在青蛙、鱼类和圆口动物中没有获得产物。对鸡、凯门鳄、龟和蛇的DNA序列进行测序后发现，凯门鳄的DNA序列与人釉原蛋白基因外显子6的对应率仅为48.5%。鸡、龟和蛇的产物具有较低的但轻微的同源性。因此，本研究表明，釉原蛋白基因类序列的釉原蛋白基因可能是普遍保守的脊椎动物。少

In order to understand the phylogenetic distribution and expression of amelogenin genes in vertebrates, Southern hybridyzation, in situ hybridyzation and PCR amplification were performed in thirteen vertebrate species selected from seven taxonomic classes. The species used in this study were as follows ; the human, mouse (Mammalia), chicken (Aves), caiman, tortoise, snake (Reptilia), frog (Amphibia), gar-pike, lungfish, eel (Osteichthyes), dogfish (Chondrichthyes) and hagfish, lamprey (Agnatha). The Southern hybridyzation assay revealed that the hybridyzation with the human cDNA non-radioactive probes was obtained in the genomic DNA of all the species used. This demonstrates partial DNA sequence similarities between these species, and may indicates the universal distribution of the amelogenin gene or amelogenin gene-like sequences in vertebrates. Then, the gar-pike was selected and was examined by in situ hybridyzation by using human cDNA non-radioactive probes, because of it's signifi … More cance for the phylogenetical location on the enamel evolutions as revealed by fine-structural and immunocytochemical analyzes. Although the hybridyzation was detected with the human cDNA probes by Southern hybridyzation, the signals of mRNA was not detected in the tooth germs of the gar-pike. Furthermore, in the PCR amplification targeted to the homologous sequences with the exon 6 of human amelogenin gene, the products were obtained in the genomic DNA of the human (400bp), mouse (400bp), chicken (780bp), caiman (400bp), tortoise (750bp) and snake (750bp). However no products were obtained in frogs, fishes and cyclostomes. After performing the sequencing of products in the chicken, caiman, tortoise and snake, the DNA sequences of the caiman only corresponded with the exon 6 of human amelogenin gene by 48.5%. A lower but slight homology were recognized in the products of the chicken, tortoiose and snake. Consequently, the present study demonstrates that the amelogenin gene of amelogenin gene-like sequences may be conserved universally in vertebrates. Less