While it is known that ScRad9 DNA damage checkpoint protein is recruited to damaged DNA by recognizing specific histone modifications, here we report a different way of Rad9 recruitment on chromatin under non DNA damaging conditions. We found Rad9 to bind directly with the copper-modulated transcriptional activator Mac1, suppressing both its DNA binding and transactivation functions. Rad9 was recruited to active Mac1-target promoters (CTR1, FRE1) and along CTR1 coding region following the association pattern of RNA polymerase (Pol) II. Hir1 histone chaperone also interacted directly with Rad9 and was partly required for its localization throughout CTR1 gene. Moreover, Mac1-dependent transcriptional initiation was necessary and sufficient for Rad9 recruitment to the heterologous ACT1 coding region. In addition to Rad9, Rad53 kinase also localized to CTR1 coding region in a Rad9-dependent manner. Our data provide an example of a yeast DNA-binding transcriptional activator that interacts directly with a DNA damage checkpoint protein in vivo and is functionally restrained by this protein, suggesting a new role for Rad9 in connecting factors of the transcription machinery with the DNA repair pathway under unchallenged conditions.

中文翻译：

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啤酒酵母Rad9蛋白的不同关联将Mac1调控的转录与DNA修复联系在一起。

虽然已知ScRad9 DNA损伤检查点蛋白通过识别特定的组蛋白修饰而被募集到受损的DNA，但在此我们报道了在非DNA损伤条件下在染色质上Rad9募集的另一种方式。我们发现Rad9直接与铜调节的转录激活因子Mac1结合，抑制其DNA结合和反式激活功能。按照RNA聚合酶（Pol）II的结合模式，将Rad9募集到有活性的Mac1目标启动子（CTR1，FRE1）并沿着CTR1编码区募集。Hir1组蛋白伴侣也直接与Rad9相互作用，部分需要在整个CTR1基因中定位。此外，Mac1依赖的转录起始是必要的，并且足以使Rad9募集到异源ACT1编码区。除了Rad9，Rad53激酶也以Rad9依赖性方式定位于CTR1编码区。我们的数据提供了一个与体内DNA损伤检查点蛋白直接相互作用并在功能上受该蛋白限制的酵母DNA结合转录激活剂的例子，这表明Rad9在转录机制与DNA修复途径的连接中起着新的作用。在没有挑战的条件下。