Post-transcriptional buffering of low nascent RNA transcription by Puf5. Post-transcriptional buffering of low nascent RNA transcription by Puf5

Gene expression is a dynamic process regulated on several layers starting with transcription, mRNA export, translation and finally, mRNA degradation. While subsequent layers heavily influence each other, it is not clear if the most extreme layers, chromatin architecture and mRNA decay are linked. Here, we show that changes in nascent transcription mediated by mutating H3K56 to alanine are buffered at a post-transcriptional level by the Pumilio protein Puf5, which stabilizes transcripts in a context-dependent manner. Depleting Puf5 in an H3K56A background leads to downregulation of its direct targets, largely consisting of ribosomal protein genes. This is followed by a decrease in translation efficiency and finally, cell cycle arrest. Importantly, we show that this phenomenon of post-transcriptional buffering is not only linked to H3K56A, but might be a more widespread phenomenon to ensure physiological mRNA levels and to maintain cellular homeostasis.