Butler D K, Yasuda L E, Yao M C
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104, USA.
Cell. 1996 Dec 13;87(6):1115-22. doi: 10.1016/s0092-8674(00)81805-x.
Many amplified genes, including some oncogenes, are organized as large inverted repeats. How such giant palindromes are generated remains largely unknown. Recent studies of a palindrome in the ciliate Tetrahymena suggest a novel mechanism that requires chromosome breakage next to short inverted repeats. The prevalence of short inverted repeats in eukaryotic genomes raises the interesting possibility that this process may occur widely as a response to chromosome damage. Here we demonstrate that in Saccharomyces cerevisiae, large DNA palindromes are formed efficiently, probably by intramolecular recombination, when a double-strand break is introduced next to short inverted repeats. These results suggest a general mechanism for large palindromic DNA formation and reveal an important new source of genome instability resulting from chromosome breakage at selective sites.
许多扩增基因，包括一些癌基因，都是以大的反向重复序列形式组织起来的。这种巨大的回文结构是如何产生的，目前仍 largely unknown。近期对纤毛虫四膜虫中一个回文结构的研究提出了一种新机制，该机制需要在短反向重复序列旁发生染色体断裂。真核生物基因组中短反向重复序列的普遍性引发了一个有趣的可能性，即这一过程可能作为对染色体损伤的一种反应而广泛发生。在这里，我们证明在酿酒酵母中，当在短反向重复序列旁引入双链断裂时，大的DNA回文结构可能通过分子内重组高效形成。这些结果提示了一种形成大的回文DNA的普遍机制，并揭示了由选择性位点的染色体断裂导致的基因组不稳定的一个重要新来源。
