In vivo double-strand breaks occur at recombinogenic G + C-rich sequences in the yeast mitochondrial genome.
In vivo double-strand breaks occur at recombinogenic G + C-rich sequences in the yeast mitochondrial genome.
复制标题
体内双链断裂发生在酵母线粒体基因组中富含重组 G C 的序列处。
DOI：
10.1073/pnas.85.8.2686
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发表时间：
1988
影响因子：
11.1
通讯作者：
Butow,RA
中科院分区：
文献类型：
--
作者：
Zinn,AR;Pohlman,JK;Perlman,PS;Butow,RA
酵母线粒体var1基因编码区的46碱基对富G + c元件（GC簇）在杂交中优先插入缺乏该序列的受体等位基因中。不像类似的基因转换事件涉及插入一个可选的1143碱基对内含子，线粒体21S rRNA基因，这需要由内含子内的基因编码的蛋白质的作用，var1 GC簇的转换不需要线粒体基因组的任何蛋白质产物。我们在未交配的单倍体rho+和rho-菌株分离的线粒体DNA中检测到了var1基因的双链断裂，这些断裂位于可选GC簇的边界或附近，以及该序列上游160个碱基对的保守拷贝。在可选GC簇靶序列附近的受体var1 DNA分子中未检测到双链断裂。这与21S rrna编码DNA （rDNA）内含子转换形成对比，在21S rrna编码DNA （rDNA）中，受体DNA而不是供体DNA在元件插入位点被切割。这些结果表明，尽管21S rDNA内含子和var1 GC簇优先插入到各自的短等位基因中，但这些转换可能是通过不同的机制发生的。
An optional 46-base-pair G + C-rich element (GC cluster) in the coding region of the yeast mitochondrial var1 gene inserts preferentially in crosses into recipient alleles that lack the sequence. Unlike a similar gene conversion event involving the insertion of an optional 1143-base-pair intron, the mitochondrial 21S rRNA gene, which requires the action of a protein encoded by a gene within that intron, conversion of the var1 GC cluster does not require any protein product of the mitochondrial genome. We have detected double-strand breaks in the var1 gene in mitochondrial DNA isolated from unmated haploid rho+ and rho- strains at or near the boundaries of the optional GC cluster, as well as at a conserved copy of that sequence 160 base pairs upstream. No double-strand breaks were detected in the recipient var1 DNA molecules in the vicinity of the optional GC cluster target sequence. This contrasts with 21S rRNA-encoding DNA (rDNA) intron conversion where the recipient, but not the donor DNA, is cleaved at the element insertion site. These results suggest that although the 21S rDNA intron and the var1 GC cluster are preferentially inserted into their respective short alleles, these conversions probably occur by different mechanisms.