Short inverted-repeat transposable elements in teleost fish and implications for a mechanism of their amplification
Short inverted-repeat transposable elements in teleost fish and implications for a mechanism of their amplification
复制标题
DOI：
10.1007/pl00006440
复制
发表时间：
1999-01-01
影响因子：
3.9
通讯作者：
Hackett, PB
中科院分区：
文献类型：
--
作者：
Izsvák, Z;Ivics, Z;Hackett, PB
Angel是第一个从鱼类中分离出来的微型反向重复转座元件（MITE），Angel元件是不完美的回文结构，具有在体外形成茎环结构的潜力。尽管物种内部和物种之间的元素序列差异高达 55%，但它们的反向重复结构得以保留，这意味着功能的重要性。我们估计大约有 10(3)-10(4) 个天使分散在整个斑马鱼基因组中，这证明该转座元件家族在进化过程中已显着扩增。天使元件和非洲爪蟾 MITE 在其末端携带共同的序列基序，表明共同的起源和/或相关的转座机制。我们提出了一个模型，其中 MITE 利用 DNA 复制的基本细胞机制进行扩增，这取决于这些元件的特征性反向重复结构。我们认为，MITE 是通过 DNA 中间体转座的基因组寄生虫，DNA 中间体是由单链 DNA 折叠形成的，它从它们所在的基因组中编码的产物中借用了所有必要的因子来进行扩增。使用Angel特异性引物通过PCR检测了不同品系斑马鱼的DNA多态性，表明这些元件与脊椎动物基因组中的其他转座子相结合，将成为基因组作图和突变遗传分析的有用分子工具。
Angel is the first miniature inverted-repeat transposable element (MITE) isolated from fish, Angel elements are imperfect palindromes with the potential to form stem-loop structures in vitro. Despite sequence divergence of elements of up to 55% within and between species, their inverted repeat structures have been maintained, implying functional importance. We estimate that there are about 10(3)-10(4) Angels scattered throughout the zebrafish genome, evidence that this family of transposable elements has been significantly amplified over the course of evolution. Angel elements and Xenopus MITEs carry common sequence motifs at their termini, indicating common origin and/or related mechanisms of transposition. We present a model in which MITEs take advantage of the basic cellular mechanism of DNA replication for their amplification, which is dependent on the characteristic inverted repeat structures of these elements. We propose that MITEs are genomic parasites that transpose via a DNA intermediate, which forms by a folding-back of a single strand of DNA, that borrow all of the necessary factors for their amplification from products encoded in the genomes in which they reside. DNA polymorphisms in different lines of zebrafish were detected by PCR using Angel-specific primers, indicating that such elements, combined with other transposons in vertebrate genomes, will be useful molecular tools for genome mapping and genetic analyses of mutations.