X-ray survival characteristics and genetic analysis for nine Saccharomyces deletion mutants that show altered radiation sensitivity
X-ray survival characteristics and genetic analysis for nine Saccharomyces deletion mutants that show altered radiation sensitivity
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DOI：
10.1534/genetics.104.028613
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Baccari, C
中科院分区：
文献类型：
--
作者：
Game, JC;Williamson, MS;Baccari, C
一系列全基因组酵母缺失突变体的出现为鉴定参与 DNA 修复的所有酵母基因提供了机会。使用 X 射线，我们正在筛选这些突变体，以确定导致对电离辐射致命效应的敏感性增加的其他基因。对于每个被鉴定为敏感的突变体，我们正在确认敏感性表型与缺失等位基因共分离，并在至少一个纯合二倍体和两个单倍体菌株中获得多点存活与剂量测定。我们提供了涉及基因 DOT1、MDM20、NAT3、SPT7、SPT20、GCN5、HFI1、DCC1 和 VID21/EAF1 的缺失突变体的数据，并讨论了它们在修复中的潜在作用。其中八个基因在删除后会产生明显的辐射敏感表型，但第九个基因 GCN5 最多会产生边缘表型。尽管一两个缺失可能具有边缘敏感性，但没有一个缺失对紫外线辐射具有显着的敏感性。 DOT1 基因之所以令人感兴趣，是因为它唯一已知的功能是甲基化组蛋白 H3 蛋白核心中的一个赖氨酸残基。我们发现该残基被其他氨基酸取代的组蛋白 H3 突变体（由 K. Struhl 提供）也对 X 射线敏感，这证实了赖氨酸 79 残基的甲基化是有效修复辐射损伤所必需的。
The availability of a genome-wide set of Saccharomyces deletion mutants provides a chance to identify all the yeast genes involved in DNA repair. Using X rays, we are screening these mutants to identify additional genes that cause increased sensitivity to the lethal effects of ionizing radiation. For each mutant identified as sensitive, we are confirming that the sensitivity phenotype cosegregates with the deletion allele and are obtaining multipoint survival-vs.-dose assays in at least one homozygous diploid and two haploid strains. We present data for deletion mutants involving the genes DOT1, MDM20, NAT3, SPT7, SPT20, GCN5, HFI1, DCC1, and VID21/EAF1 and discuss their potential roles in repair. Eight of these genes cause a clear radiation-sensitive phenotype when deleted, but the ninth, GCN5, results in at most a borderline phenotype. None of the deletions confer substantial sensitivity to ultraviolet radiation, although one or two may confer marginal sensitivity. The DOT1 gene is of interest because its only known function is to methylate one lysine residue in the core of the histone H3 protein. We find that histone H3 mutants (supplied by K. Struhl) in which this residue is replaced by other amino acids are also X-ray sensitive, which confirms that methylation of the lysine-79 residue is required for effective repair of radiation damage.