Mutations affecting RNA polymerase I-stimulated exchange and rDNA recombination in yeast.
Mutations affecting RNA polymerase I-stimulated exchange and rDNA recombination in yeast.
复制标题
影响酵母中 RNA 聚合酶 I 刺激的交换和 rDNA 重组的突变。
DOI：
10.1093/genetics/127.1.31
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发表时间：
1991
期刊：
影响因子：
3.3
通讯作者：
Keil,RL
中科院分区：
文献类型：
--
作者：
Lin,YH;Keil,RL
HOT1是从酵母的rDNA重复单元中分离出来的顺式作用的重组刺激序列。HOT1刺激有丝分裂交换的能力似乎取决于其促进高水平RNA聚合酶I转录的能力。开发了一种定性菌落颜色分割试验，以筛选改变HOT1活性的反式作用突变。分离出低重组和高重组突变体。对7个降低HOT1活性的HOT1重组突变体（hrm）的遗传分析表明，它们表现为隐性核突变，属于5个连锁群。其中三个突变，hrm1、hrm2和hrm3，也会减少rDNA交换，但在没有HOT1的情况下不会改变重组。另一个突变，hrm4，减少HOT1刺激下的重组，但在没有HOT1的情况下不影响rDNA的重组或交换。利用该筛选还分离到了2个新的RAD52等位基因。关于HOT1的活性，rad52对所有四个hrm突变都是上位性的，这表明hrm基因的产物和rad52介导了相同重组途径的步骤。发现降低HOT1活性和rDNA交换的突变支持了HOT1在rDNA重组中起作用的假设。
HOT1 is a cis-acting recombination-stimulatory sequence isolated from the rDNA repeat unit of yeast. The ability of HOT1 to stimulate mitotic exchange appears to depend on its ability to promote high levels of RNA polymerase I transcription. A qualitative colony color sectoring assay was developed to screen for trans-acting mutations that alter the activity of HOT1. Both hypo-recombination and hyper-recombination mutants were isolated. Genetic analysis of seven HOT1 recombination mutants (hrm) that decrease HOT1 activity shows that they behave as recessive nuclear mutations and belong to five linkage groups. Three of these mutations, hrm1, hrm2, and hrm3, also decrease rDNA exchange but do not alter recombination in the absence of HOT1. Another mutation, hrm4, decreases HOT1-stimulated recombination but does not affect rDNA recombination or exchange in the absence of HOT1. Two new alleles of RAD52 were also isolated using this screen. With regard to HOT1 activity, rad52 is epistatic to all four hrm mutations indicating that the products of the HRM genes and of RAD52 mediate steps in the same recombination pathway. Finding mutations that decrease both the activity of HOT1 and exchange in the rDNA supports the hypothesis that HOT1 plays a role in rDNA recombination.