Cell functionality relies on the communication between its pathways, processes and machineries. This becomes even more critical for proper responses to stresses. Our group has been at the forefront of deciphering the crosstalk between transcription and post-transcriptional stages - a key component in this communication. Previously, we discovered that two yeast proteins bind RNA polymerase II transcripts co-transcriptionally, accompany these transcripts during transport, translation and decay. We named this phenomenon ‘mRNA imprinting”. Here a novel method is described, revealing that mRNA imprinting is a wide-spread phenomenon, involving dozens of proteins, some unexpected as the are known to function in the cytoplasm. One of them, Ssa2, an HSP70 variant, imprints mRNAs mainly during heat shock (HS). Hsp70 is a chaperone that folds proteins co-translationally. Here we focus on Ssa2 as a proof of principle. We hypothesize that, during HS, Ssa2 binds specific HS mRNAs cotranscriptionally and serves as a “personal” chaperon of their products (see scheme). This may represent a novel mechanism of the stress response. Indeed, our preliminary data showed that by actively evicting Ssa2 from the nucleus, using the "anchor away" technique, cell do not cope well with HS. Moreover, the Ssa2-imprinting
paradigm opens a new direction for studying how transcription can remotely regulate translation. Using novel approaches, we will examine whether the imprinted Ssa2 is transported, together with specific HS mRNAs, to the ribosome.