Transcript profiling of Saccharomyces cerevisiae cells overexpressing YOX1 before and after 2 and 4 hours of hydroxyurea (HU) treatment (200 mM)

mRNA processing bodies (P-bodies) are cytoplasmic granules that form in eukaryotic cells in response to numerous stresses to serve as sites of degradation and storage of mRNAs. Functional P-bodies are critical for the DNA replication stress response in yeast, yet the repertoire of P-body targets and the mechanisms by which P-bodies promote replication stress resistance are unknown. In this study, we identify the complete complement of mRNA targets of P-bodies during replication stress induced by hydroxyurea treatment. The key P-body protein Lsm1 controls the abundance of HHT1, ACF4, ARL3, TMA16, RRS1 and YOX1 mRNAs to prevent their toxic accumulation during replication stress. Accumulation of YOX1 mRNA causes aberrant down-regulation of a network of genes critical for DNA replication stress resistance. Among these genes we identify ALD6, whose de-repression is critical to prevent accumulation of acetaldehyde, a strongly toxic molecule during DNA replication stress.mRNA加工小体（mRNA processing bodies，P-bodies）是真核细胞中响应多种应激而形成的细胞质颗粒，可作为mRNA降解与储存的位点。功能性P-bodies对酵母的DNA复制应激反应至关重要，但目前尚不清楚P-body的靶标谱以及其促进复制应激抗性的具体机制。本研究鉴定了羟基脲（hydroxyurea）处理诱导的复制应激状态下，P-bodies的全部mRNA靶标。关键P-body蛋白Lsm1可调控HHT1、ACF4、ARL3、TMA16、RRS1及YOX1的mRNA丰度，以避免它们在复制应激过程中发生毒性积累。YOX1 mRNA的异常积累会导致一系列对DNA复制应激抗性至关重要的基因网络出现异常下调。在这些靶基因中，我们鉴定出ALD6，其去抑制作用对于防止乙醛（acetaldehyde）的积累至关重要，而乙醛是DNA复制应激期间一种强毒性分子。