Aleksenko A, Gems D, Clutterbuck J
Division of Molecular Genetics, University of Glasgow, UK.
Mol Microbiol. 1996 Apr;20(2):427-34. doi: 10.1111/j.1365-2958.1996.tb02629.x.
The AMA1 sequence is an efficient plasmid replicator and transformation enhancer in Aspergillus nidulans. It comprises two long perfect inverted repeats (MATE elements) flanking a short, unique, central spacer. Subclone analysis indicates that the complete inverted duplication, but not the unique central spacer, is necessary for efficient plasmid replication. The smallest fragments able to affect transformation efficiency lie within the AT-rich portions of the inverted repeats. We demonstrate that two or more copies of the repeat in any relative orientation are able to perform the replicator function. A single copy of a MATE element increases transformation frequency to a modest extent but leads to multiple rearrangement, unstable integration or concatenation of vector molecules. Multimeric concatenates generated during this process are more sable mitotically, and when reisolated, transform the fungus at a much higher frequency than the original monomeric vector. Selection for multiple products which resemble amplified DNA in various eukaryotic systems.
AMA1序列是构巢曲霉中一种高效的质粒复制子和转化增强子。它由两个长的完美反向重复序列（MATE元件）组成，两侧是一个短的、独特的中央间隔区。亚克隆分析表明，完整的反向重复序列而非独特的中央间隔区对于高效的质粒复制是必需的。能够影响转化效率的最小片段位于反向重复序列的富含AT的部分。我们证明，两个或更多拷贝的重复序列以任何相对方向都能够执行复制子功能。单个MATE元件拷贝在一定程度上提高了转化频率，但会导致载体分子的多次重排、不稳定整合或串联。在此过程中产生的多聚体串联体在有丝分裂时更稳定，重新分离时，其转化真菌的频率比原始单体载体高得多。选择多种产物，这些产物类似于各种真核系统中的扩增DNA。
