STRUCTURAL CONSERVATION AND VARIATION IN THE D-LOOP-CONTAINING REGION OF VERTEBRATE MITOCHONDRIAL-DNA
STRUCTURAL CONSERVATION AND VARIATION IN THE D-LOOP-CONTAINING REGION OF VERTEBRATE MITOCHONDRIAL-DNA
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DOI：
10.1016/0022-2836(86)90272-x
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发表时间：
1986-12-05
影响因子：
5.6
通讯作者：
SBISA, E
中科院分区：
文献类型：
--
作者：
BROWN, GG;GADALETA, G;SBISA, E
本文报道了三种大鼠线粒体DNA（mtDNA）的D环区核苷酸序列，其中两种来自褐家鼠（Rattus norvegicus），另一种来自红毛鼠（R. Rattus，were determined.这些序列之间的比较和与小鼠序列表明，在碱基组成和频率的核苷酸改变的基础上，可以定义三个域内的D-环的区域：一个中央保守的部分，穷人在L-链腺嘌呤，两侧由两个不同的，腺嘌呤丰富的区域。发现在这些序列中以出乎意料的高频率发生缺失和插入，并且发现称为CSB-1的保守序列块在R. Rattus序列虽然在比较亲缘关系较远的mtDNA时，D环区在分子上的差异最大，但它并不比R. norvegicus和R. Rattus，其中央保守结构域似乎是该分子最保守的区域之一。最可变的结构域与tRNAPhe基因邻接，并含有L和H-链启动子和用于H-链DNA合成的5“末端。在这一区域内，我们发现了所有我们检测过的mtDNA序列，包括人类、两种偶蹄动物和非洲爪蟾的mtDNA序列，它们都能够折叠成三叶草结构。在相同mtDNA的其他不同结构域中，我们发现能够在D-环DNA合成终止位点处或附近重现类似二级结构构型的序列。尽管它们发生的区域的初级结构差异很高，但形成这种结构的潜力的进化保存表明，这些结构对于在含有D环的区域发生的一些过程是至关重要的。
The nucleotide sequences of the D-loop-containing regions of three rat mitochondrial DNAs (mtDNAs), two from the species Rattus norvegicus and one from R. rattus, were determined. Comparisons made among these sequences and with the mouse sequence showed that, on the basis of both base composition and frequency of nucleotide alterations, three domains could be defined within the D-loop-containing region: a central conserved segment, poor in L-strand adenine, flanked by two divergent, adenine-rich regions. Deletions and insertions were found to occur at an unexpectedly high frequency in these sequences and the conserved sequence block called CSB-1 was found not to be intact in the R. rattus sequence. Although in comparisons of more distantly related mtDNAs the D-loop region is the most divergent on the molecule, it does not diverge more than typical protein genes between R. norvegicus and R. rattus, and its central conserved domain appears to be one of the molecule''s most conserved regions. The most variable domain borders the tRNAPhe gene and contains the L and H-strand promoters and the 5'' terminus for H-strand DNA synthesis. Within this region we have found sequences in all the mtDNAs we have examined, including those of human, two artiodactyls and Xenopus, that are capable of folding into cloverleaf structures. In the other divergent domain of the same mtDNAs, we find sequences capable of assumming similar secondary structural configurations at or near the sites for the termination of D-loop DNA synthesis. The evolutionary preservation of the potential to form such structures despite the high primary-structural divergence of the regions they occur in, suggests the structures are of principal importance for some processes occurring in the D-loop-containing region.