Shao Zhiyong, Graf Shannon, Chaga Oleg Y, Lavrov Dennis V
Interdepartmental Genetics Graduate Program, Iowa State University, Ames, Iowa 50011, USA.
Gene. 2006 Oct 15;381:92-101. doi: 10.1016/j.gene.2006.06.021. Epub 2006 Jul 18.
The 16,937-nuceotide sequence of the linear mitochondrial DNA (mt-DNA) molecule of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa) - the first mtDNA sequence from the class Scypozoa and the first sequence of a linear mtDNA from Metazoa - has been determined. This sequence contains genes for 13 energy pathway proteins, small and large subunit rRNAs, and methionine and tryptophan tRNAs. In addition, two open reading frames of 324 and 969 base pairs in length have been found. The deduced amino-acid sequence of one of them, ORF969, displays extensive sequence similarity with the polymerase [but not the exonuclease] domain of family B DNA polymerases, and this ORF has been tentatively identified as dnab. This is the first report of dnab in animal mtDNA. The genes in A. aurita mtDNA are arranged in two clusters with opposite transcriptional polarities; transcription proceeding toward the ends of the molecule. The determined sequences at the ends of the molecule are nearly identical but inverted and lack any obvious potential secondary structures or telomere-like repeat elements. The acquisition of mitochondrial genomic data for the second class of Cnidaria allows us to reconstruct characteristic features of mitochondrial evolution in this animal phylum.
已确定了海月水母（刺胞动物门，钵水母纲）线性线粒体DNA（mt-DNA）分子的16,937个核苷酸序列——这是钵水母纲的首个mtDNA序列，也是后生动物的首个线性mtDNA序列。该序列包含13种能量途径蛋白、小亚基和大亚基rRNA以及甲硫氨酸和色氨酸tRNA的基因。此外，还发现了两个长度分别为324和969个碱基对的开放阅读框。其中一个，即ORF969，推导的氨基酸序列与B族DNA聚合酶的聚合酶结构域[而非核酸外切酶结构域]显示出广泛的序列相似性，该ORF已被初步鉴定为dnab。这是动物mtDNA中dnab的首次报道。海月水母mtDNA中的基因排列成两个转录极性相反的簇；转录朝着分子末端进行。分子末端确定的序列几乎相同但方向相反，并且缺乏任何明显的潜在二级结构或端粒样重复元件。刺胞动物门第二类线粒体基因组数据的获取使我们能够重建该动物门线粒体进化的特征。
