Recombinational telomere elongation promoted by DNA circles
Recombinational telomere elongation promoted by DNA circles
复制标题
DOI：
10.1128/mcb.22.13.4512-4521.2002
复制
发表时间：
2002-07-01
影响因子：
5.3
通讯作者：
McEachern, MJ
中科院分区：
文献类型：
--
作者：
Natarajan, S;McEachern, MJ
缺乏端粒酶的酵母突变体能够通过依赖于同源重组的替代机制来维持端粒。在这里，我们表明，通过使用含有两种类型的端粒重复的乳酸克鲁维酵母细胞，重组端粒延长产生的重复模式中常见的大多数或所有端粒的幸存者，保留两种重复类型。我们认为，这些模式产生于端粒DNA的小圆圈被用作滚环基因转换的模板，并且来自延长的端粒的序列通过额外的、更典型的基因转换事件传播到其他端粒。与此相一致的是，人工构建的含有端粒重复序列的DNA环在转化到K.乳细胞用两种端粒环进行的混合实验表明，转化序列的所有整合拷贝都来自单个原始环状分子。
Yeast mutants lacking telomerase are capable of maintaining telomeres by an alternate mechanism that depends on homologous recombination. We show here, by using Kluyveromyces lactis cells containing two types of telomeric repeats, that recombinational telomere elongation generates a repeating pattern common in most or all telomeres in survivors that retain both repeat types. We propose that these patterns arise from small circles of telomeric DNA being used as templates for rolling-circle gene conversion and that the sequence from the lengthened telomere is spread to other telomeres by additional, more typical gene conversion events. Consistent with this, artificially constructed circles of DNA containing telomeric repeats form long tandem arrays at telomeres when transformed into K. lactis cells. Mixing experiments done with two species of telomeric circles indicated that all of the integrated copies of the transforming sequence arise from a single original circular molecule.