Mammalian mitochondrial D-loop region structural analysis:: identification of new conserved sequences and their functional and evolutionary implications
Mammalian mitochondrial D-loop region structural analysis:: identification of new conserved sequences and their functional and evolutionary implications
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DOI：
10.1016/s0378-1119(97)00404-6
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发表时间：
1997-12-31
期刊：
影响因子：
3.5
通讯作者：
Saccone, C
中科院分区：
文献类型：
--
作者：
Sbisà, E;Tanzariello, F;Saccone, C
本文报道了第一次全面分析的位移环（D-loop）区域序列从10个不同的哺乳动物目。它代表了一个系统的进化研究，在分子水平上的调节同源区域的生物体属于一个明确定义的类，哺乳动物，辐射约1.5亿年前（Mya）。我们已经比对和分析了26个完整的D-环区序列，可在文献中和脂肪睡鼠序列，最近在我们的实验室确定。我们的比对的新奇包括通过计算机程序获得的初步输出的广泛手动修订，以优化序列相似性，特别是对于显示长度异质性和存在重复序列的两个外围域。多重比对可在WWW网站：http://www.ba.cnr.it/dloop.html上获得。我们的比较研究，使我们能够确定新的保守序列块存在于所有考虑中的物种和事件的插入/删除，在功能和进化方面都有重要的影响。特别是，我们已经检测到两个块，约60 bp长，延长终止相关序列（ETAS 1和ETAS 2）在所有考虑的生物体中保守。对实验工作的评价表明，ETAS 1和ETAS 2在复制和转录调控中可能发挥功能作用，并提出了有针对性的实验方法。对保守序列块（CSB）的分析清楚地表明，CSB 1是唯一非常重要的元件，为所有哺乳动物线粒体基因组所共有，而CSB 2和CSB 3可能参与不同但相关的功能，可能具有物种特异性，因此与核线粒体共同进化过程更有联系。我们的假设上的不同功能的保守元件，CSB和塔斯的影响，迄今为止报道的主要调控信号，将解释这些元素在进化中的不同保护。此外，内部顺序比较的D-环区域突出了独特的功能，有助于定义该地区的进化动力学密切相关的物种。(C)1997年Elsevier Science B.V.
This paper reports the first comprehensive analysis of Displacement loop (D-loop) region sequences from ten different mammalian orders. It represents a systematic evolutionary study at the molecular level on regulatory homologous regions in organisms belonging to a well defined class, mammalia, which radiated about 150 million years ago (Mya). We have aligned and analyzed 26 complete D-loop region sequences available in the literature and the fat dormouse sequence, recently determined in our laboratory. The novelty of our alignment consists of the extensive manual revision of the preliminary output obtained by computer program to optimize sequence similarity, particularly for the two peripheral domains displaying heterogeneity in length and the presence of repeated sequences. The multialignment is available at the WWW site: http://www.ba.cnr.it/dloop.html. Our comparative study has allowed us to identify new conserved sequence blocks present in all the species under consideration and events of insertion/deletion which have important implications in both functional and evolutionary aspects. In particular we have detected two blocks, about 60 bp long, extended termination associated sequences (ETAS1 and ETAS2) conserved in all the organisms considered. Evaluation against experimental work suggests a possible functional role of ETAS1 and ETAS2 in the regulation of replication and transcription and targeted experimental approaches. The analyses on conserved sequence blocks (CSBs) clearly indicate that CSB1 is the only very essential element, common to all mammalian mt genomes, while CSB2 and CSB3 could be involved in different though related functions, probably species specific, and thus more linked to nuclear-mitochondrial coevolutionary processes. Our hypothesis on the different functional implications of the conserved elements, CSBs and TASs, reported so far as main regulatory signals, would explain the different conservation of these elements in evolution. Moreover the intra-order comparison of the D-loop regions highlights peculiar features useful to define the evolutionary dynamics of this region in closely related species. (C) 1997 Elsevier Science B.V.