A Temperature Increase Induces Atf1/Pcr1-Dependent Rapid Depletion of Histones in Transcriptionally Activated Gene Bodies in Fission Yeast.

Transcriptional regulation is central to organisms' response and adaptation to environmental changes. However, the coordination of transcriptional machinery with chromatin when rapid transcriptional changes are needed is largely unknown. Here, we studied the rapid response of histone modifications upon heat treatment of fission yeast Schizosaccharomyces pombe. We observed a significant eviction of H3 in the transcribed regions of upregulated genes, named Hasty Overheat-Triggered Differentially Occupied Genes (HOT-DOGs), including Heat Shock Protein-encoding genes. The loss of H3 in a third of the HOT-DOGs was dependent on the Atf1-Pcr1 transcription factor complex. Furthermore, the H3K9 methyltransferase Clr4 likely modulates the rate of transcription elongation and helps prevent transcriptional read-through beyond polyadenylation sites in these genes. Our results unveiled a novel function of Clr4 in regulating the dynamics of transcription within gene bodies and provided insights into how cells cope with rapid environmental changes while preserving chromatin integrity.