Local DNA sequence control of deletion formation in Escherichia coli plasmid pBR322.
Local DNA sequence control of deletion formation in Escherichia coli plasmid pBR322.
复制标题
大肠杆菌质粒 pBR322 中缺失形成的局部 DNA 序列控制。
DOI：
10.1093/genetics/115.1.41
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发表时间：
1987
期刊：
影响因子：
3.3
通讯作者：
Berg,DE
中科院分区：
文献类型：
--
作者：
DasGupta,U;Weston-Hafer,K;Berg,DE
使用涉及回文插入突变逆转的测试研究了缺失形成的特异性。pBR322质粒ampicillin- resistant （amp）基因中一个tn5相关转座子在13个位点上的插入被缩短为一套完整的回文序列，长度分别为22、32和90bp。我们监测了Ampr还原的频率，这是删除回文加上一个侧面9bp直接重复序列（通过转位形成）的结果。发现反转频率取决于回文插入的位置和顺序。在13个位点中，将45 kb的中断回文变为22 bp的完整回文可促进缺失形成，其影响因子从4倍到545倍不等，而将完整回文从22 bp延长到90 bp可促进缺失形成，其影响因子从8倍到1.8万倍不等。我们得出结论，缺失的形成受到DNA序列或构象的微妙特征的强烈影响，无论是在缺失片段的内部还是外部，这些影响可能反映了DNA加工蛋白与模板DNA的特定相互作用。
The specificity of deletion formation was studied using tests involving reversion of palindromic insertion mutations. Insertions of a Tn5-related transposon at 13 sites in the ampicillin-resistance (amp) gene of plasmid pBR322 were shortened to a nested set of perfect palindromes, 22, 32 and 90 bp long. We monitored frequencies of reversion to Ampr, which is the result of deletion of the palindrome plus one copy of the flanking 9 bp direct repeats (which had been formed by transposition). Revertant frequencies were found to depend on the location and the sequence of the palindromic insert. Changing a 45-kb interrupted palindrome to a 22-bp perfect palindrome stimulated deletion formation by factors of from fourfold to 545-fold among the 13 sites, while elongation of the perfect palindrome from 22 to 90 bp stimulated deletion formation by factors of from eight- to 18,000-fold. We conclude that deletion formation is strongly affected by subtle features of DNA sequence or conformation, both inside and outside the deleted segment, and that these effects may reflect specific interactions of DNA processing proteins with template DNAs.