Gene expression involves regulation of chromatin structure and transcription, as well as processing of the transcribed mRNA. While there are feedback mechanisms, it is not clear whether these include crosstalk between chromatin architecture and mRNA decay. To address this, we performed a genome-wide genetic screen using a Saccharomyces cerevisiae strain harbouring the H3K56A mutation, which is known to perturb chromatin structure and nascent transcription. We identified Puf5 (also known as Mpt5) as essential in an H3K56A background. Depletion of Puf5 in this background leads to downregulation of Puf5 targets. We suggest that Puf5 plays a role in post-transcriptional buffering of mRNAs, and support this by transcriptional shutoff experiments in which Puf5 mRNA targets are degraded slower in H3K56A cells compared to wild-type cells. Finally, we show that post-transcriptional buffering of Puf5 targets is widespread and does not occur only in an H3K56A mutant, but also in an H3K4R background, which leads to a global increase in nascent transcription. Our data suggest that Puf5 determines the fate of its mRNA targets in a context-dependent manner acting as an mRNA surveillance hub balancing deregulated nascent transcription to maintain physiological mRNA levels.

中文翻译：

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RNA 结合蛋白 Puf5 有助于缓冲染色质介导的新生转录变化中的 mRNA。

基因表达涉及染色质结构和转录的调节，以及转录的 mRNA 的加工。虽然存在反馈机制，但尚不清楚这些机制是否包括染色质结构和 mRNA 衰变之间的串扰。为了解决这个问题，我们使用含有 H3K56A 突变的酿酒酵母菌株进行了全基因组遗传筛选，已知该突变会扰乱染色质结构和新生转录。我们确定 Puf5（也称为 Mpt5）在 H3K56A 背景中至关重要。在这种背景下，Puf5 的消耗会导致 Puf5 靶点的下调。我们认为 Puf5 在 mRNA 的转录后缓冲中发挥作用，并通过转录关闭实验支持了这一点，其中与野生型细胞相比，Puf5 mRNA 靶标在 H3K56A 细胞中降解得更慢。最后，我们发现 Puf5 靶标的转录后缓冲是广泛存在的，不仅发生在 H3K56A 突变体中，而且也发生在 H3K4R 背景中，这导致新生转录的整体增加。我们的数据表明，Puf5 以上下文相关的方式决定其 mRNA 靶标的命运，充当 mRNA 监视中心，平衡失调的新生转录以维持生理 mRNA 水平。