Most eukaryotic genomes encode multiple RecQ family helicases, including five such enzymes in humans. For many years, the yeast Saccharomyces cerevisiae was considered unusual in that it only contained a single RecQ helicase, named Sgs1. However, it has recently been discovered that a second RecQ helicase, called Hrq1, resides in yeast. Both Hrq1 and Sgs1 are involved in genome integrity, functioning in processes such as DNA inter-strand crosslink repair, double-strand break repair, and telomere maintenance. However, it is unknown if these enzymes interact at a genetic, physical, or functional level as demonstrated for their human homologs. Thus, we performed synthetic genetic array (SGA) analyses of hrq1 and sgs1 mutants. As inactive alleles of helicases can demonstrate dominant phenotypes, we also performed SGA analyses on the hrq1-K318A and sgs1-K706A ATPase/helicase-null mutants, as well as all combinations of deletion and inactive double mutants. We crossed these eight query strains (hrq1, sgs1, hrq1-K318A, sgs1-K706A, hrq1 sgs1, hrq1 sgs1-K706A, hrq1-K318A sgs1, and hrq1-K318A sgs1-K706A) to the S. cerevisiae single gene deletion and temperature-sensitive allele collections to generate double and triple mutants and scored them for synthetic positive and negative genetic effects based on colony growth. These screens identified hundreds of synthetic interactions, supporting the known roles of Hrq1 and Sgs1 in DNA repair, as well as suggesting novel connections to rRNA processing, mitochondrial DNA maintenance, transcription, and lagging strand synthesis during DNA replication.

大多数真核基因组编码多种RecQ家族解旋酶，包括人类中的5种此类酶。多年来，人们一直认为酿酒酵母不寻常，因为它仅包含一个单一的RecQ解旋酶，即Sgs1。但是，最近发现在酵母中存在第二个称为Hrq1的RecQ解旋酶。Hrq1和Sgs1都参与基因组完整性，在DNA链间交联修复，双链断裂修复和端粒维护等过程中起作用。但是，尚不清楚这些酶是否在遗传，物理或功能水平上相互作用，如其人类同源物所证明的那样。因此，我们对hrq1 D和sgs1 D进行了合成遗传阵列（SGA）分析突变体。由于解旋酶的失活等位基因可以显示显性表型，因此我们还对hrq1-K318A和sgs1-K706A ATPase /解旋酶无效突变体以及缺失和失活双重突变体的所有组合进行了SGA分析。我们穿过这八个查询株（hrq1D，sgs1D，hrq1-K318A，SGS1-K706A，hrq1D SGS1 d，hrq1D SGS1-K706A，hrq1-K318A sgs1D和hrq1-K318A SGS1-K706A）的酿酒酵母单基因缺失和对温度敏感的等位基因集合，以产生双突变和三突变，并根据菌落的生长对它们进行合成的正和负遗传效应评分。这些筛选确定了数百种合成相互作用，支持了Hrq1和Sgs1在DNA修复中的已知作用，并暗示了与rRNA加工，线粒体DNA维持，转录和DNA复制过程中滞链合成的新型连接。