Mignotte F, Gueride M, Champagne A M, Mounolou J C
Laboratoire de Biologie Générale-URA 1354, Université de Paris-Sud, Orsay, France.
Eur J Biochem. 1990 Dec 12;194(2):561-71. doi: 10.1111/j.1432-1033.1990.tb15653.x.
In rabbit we observed heteroplasmy at an exceptionally high level, the heterogeneity occurring within the non-coding region of the DNA. Mitochondrial DNA (mt DNA) was cloned in pBR322 and the nucleotide sequence analysis of an EcoRI-Hind III fragment encompassing the non-coding region revealed that although there are common features with other mammalian mtDNAs (termed large central-conserved-sequence block, conserved-sequence blocks 1, 2 and 3 and termination-associated elements) the non-coding region shows an unusual organization; two stretches of tandem repeats of 20 bp and 153 bp are present in a part containing the origin of H-strand replication (OH) and probably the promoters for transcription as judged from other vertebrates. The long repeats are located between tRNA(Phe) and conserved sequence block 3 and the short repeats are located between conserved sequence blocks 1 and 2. When cloned in Escherichia coli (recA or recBC sbcb) DNA fragments containing the short repeats show length differences corresponding to various copy numbers of repeats. Electrophoretic analysis of the appropriate restriction fragments of rabbit mtDNA reveals extended intra- and inter-individual length heterogeneity. Both sets of repeats are involved in the generation of heterogeneity and are present in variable copy numbers from one mtDNA molecule to another. Moreover, rearrangement of the motives of the short repeat are observed to different extents in the mtDNA from one animal to another. The occurrence, maintenance and possible involvement of these repeated sequences, capable of forming stable secondary structures, are discussed in relation to their location in the region of control signals.
在兔子中，我们观察到了异常高水平的异质性，这种异质性发生在DNA的非编码区域内。线粒体DNA（mtDNA）被克隆到pBR322中，对包含非编码区域的EcoRI - Hind III片段进行核苷酸序列分析表明，尽管与其他哺乳动物的mtDNA有共同特征（称为大的中央保守序列块、保守序列块1、2和3以及终止相关元件），但非编码区域呈现出不同寻常的组织形式；在包含H链复制起点（OH）的部分存在两段分别为20 bp和153 bp的串联重复序列，从其他脊椎动物判断，这可能也是转录启动子所在位置。长重复序列位于tRNA（Phe）和保守序列块3之间，短重复序列位于保守序列块1和2之间。当克隆到大肠杆菌（recA或recBC sbcb）中时，含有短重复序列的DNA片段显示出与重复序列不同拷贝数相对应的长度差异。对兔mtDNA的适当限制性片段进行电泳分析，揭示了个体内和个体间广泛的长度异质性。两组重复序列都参与了异质性的产生，并且在不同的mtDNA分子中以可变的拷贝数存在。此外，在不同动物的mtDNA中观察到短重复序列的基序在不同程度上发生了重排。本文讨论了这些能够形成稳定二级结构的重复序列的出现、维持及其可能的作用，以及它们在控制信号区域中的位置关系。
