Cellular mRNA levels, particularly under stress conditions, can be finely regulated by the coordinated action of transcription and degradation processes. Elements of the 5′-3′ mRNA degradation pathway, functionally associated with the exonuclease Xrn1, can bind to nuclear chromatin and modulate gene transcription. Within this group are the so-called decapping activators, including Pat1, Dhh1, and Lsm1. In this work, we have investigated the role of Pat1 in the yeast adaptive transcriptional response to cell wall stress. Thus, we demonstrated that in the absence of Pat1, the transcriptional induction of genes regulated by the Cell Wall Integrity MAPK pathway was significantly affected, with no effect on the stability of these transcripts. Furthermore, under cell wall stress conditions, Pat1 is recruited to Cell Wall Integrity-responsive genes in parallel with the RNA Pol II complex, participating both in pre-initiation complex assembly and transcriptional elongation. Indeed, strains lacking Pat1 showed lower recruitment of the transcription factor Rlm1, less histone H3 displacement at Cell Wall Integrity gene promoters, and impaired recruitment and progression of RNA Pol II. Moreover, Pat1 and the MAPK Slt2 occupied the coding regions interdependently. Our results support the idea that Pat1 and presumably other decay factors behave as transcriptional regulators of Cell Wall Integrity-responsive genes under cell wall stress conditions.

中文翻译：

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mRNA 脱帽激活剂 Pat1 是通过细胞壁完整性 MAPK 途径实现高效酵母适应性转录反应所必需的

细胞 mRNA 水平，特别是在应激条件下，可以通过转录和降解过程的协调作用进行精细调节。 5'-3' mRNA 降解途径的元件在功能上与核酸外切酶 Xrn1 相关，可以与核染色质结合并调节基因转录。该组中有所谓的脱盖激活剂，包括 Pat1、Dhh1 和 Lsm1。在这项工作中，我们研究了 Pat1 在酵母对细胞壁应激的适应性转录反应中的作用。因此，我们证明，在 Pat1 缺失的情况下，受细胞壁完整性 MAPK 通路调控的基因的转录诱导受到显着影响，但对这些转录本的稳定性没有影响。此外，在细胞壁应激条件下，Pat1 与 RNA Pol II 复合物同时被招募到细胞壁完整性响应基因，参与起始前复合物组装和转录延伸。事实上，缺乏 Pat1 的菌株表现出转录因子 Rlm1 的招募较低、细胞壁完整性基因启动子处的组蛋白 H3 置换较少以及 RNA Pol II 的招募和进展受损。此外，Pat1和MAPK Slt2相互依赖地占据编码区。我们的结果支持这样的观点：Pat1 和可能的其他衰变因子在细胞壁应激条件下充当细胞壁完整性响应基因的转录调节因子。