Molecular mechanisms driving transcriptional stress responses.

Proteotoxic stress, that is, stress caused by protein misfolding and aggregation, triggers the rapid and global reprogramming of transcription at genes and enhancers. Genome-wide assays that track transcriptionally engaged RNA polymerase II (Pol II) at nucleotide resolution have provided key insights into the underlying molecular mechanisms that regulate transcriptional responses to stress. In addition, recent kinetic analyses of transcriptional control under heat stress have shown how cells 'prewire' and rapidly execute genome-wide changes in transcription while concurrently becoming poised for recovery. The regulation of Pol II at genes and enhancers in response to heat stress is coupled to chromatin modification and compartmentalization, as well as to co-transcriptional RNA processing. These mechanistic features seem to apply broadly to other coordinated genome-regulatory responses.