脊椎动物的线粒体DNA(mtDNA)是一段长度约为15-22Kb的环形片段,具有相对的保守性。D-loop区是线粒体基因组中的非编码区域的一部分,具有控制和调节的功能。本文采用LA-PCR和生物信息学的方法,研究了大蹼铃蟾的线粒体基因组D-loop区序列,其D-loop区具有三个保守序列(CSB-1,CSB-2 and CSB-3),在5`和3`端还有独特的串联重复序列。通过分析总结其串联重复序列的特征和规律,有助于研究蛙科动物线粒体基因组进化机制。
The Mest （mesoderm-specific transcript） gene has been considered an imprinting gene in human and mouse, and was also confirmed in other mammals and flowering plants. To investigate the function and evolution of this gene, the cDNA of full length Mest gene was obtained using 5＇- and 3＇-RACE from the Chinese Large Toad （Bufo gargarizans）. The transcript is 1 325bp in length which contains a complete open reading frame （ORF） encoding a polypeptide of 326 amino acids （GenBank accession number： ABQ10905）. There is a typical 0./13 hydrolase fold domain in the putative gene product, and it shows high similarity to sequence of homologous protein of Xenopus tropicali （86%）, mammlian （70% - 80%）. RT-PCR （reverse transcriptase-polymerase chain reaction） analysis demonstrated that the Bufo gargarizans Mest （BgMest） gene is expressed widely in testis, ovary, liver, kidney, spleen, brain, stomach and lung. The conservation of the BgMest gene sequences, protein secondary structure of the BgMest protein, in addition to the expression pattern of the BgMest gene, suggested that the function of BgMest was conserved in amphibians. However, the phylogenetic tree of the imprinting gene of the mammals and other vertebrates examined in this study indicated their divergent origins.
线粒体基因是动物起源进化及群体遗传分析的理想研究对象,其中的12S和16SrRNA这两个保守序列研究比较广泛。本文以花臭蛙(Odorrana schmackeri)为实验材料,采用TIANamp Genomic DNA Kit血液/细胞/组织基因组DNA提取试剂盒提取花臭蛙肌肉组织基因组DNA,并利用聚合酶链式反应(PCR)技术进行扩增得到线粒体上12S和16SrRNA的保守片段,采用琼脂糖凝胶电泳技术对扩增产物进行检测,最后对两段基因序列进行测定并进一步分析,分别得到347bp和380bp的碱基序列。
