Study of ribosome dynamics after osmotic stress in Lsm1 and Pat1 deletions. Study of ribosome dynamics after osmotic stress in Lsm1 and Pat1 deletions

In this study, we aim to understand how the fates of stress-activated mRNAs are determined under stress conditions by isolating individual osmostress-activated mRNA species, quantitating the proteins associated in vivo with each of them, and analyzing how deletion of these proteins impact on the expression of stress-activated genes. By comparison with the proteome associated with individual not stress-related mRNA species, we show specific proteins to be preferentially binding to osmostress-activated mRNAs, notably members of the cytoplasmic Pat1 / Lsm1 – 7 complex. We evaluated the impact of this complex on the stress response by analyzing expression of osmostress-activated genes, production of osmo-protein and, mapping ribosome transit at single nucleotide resolution using 5’-phosphate sequencing of mRNAs in lsm1 and pat1 mutants. We conclude that our biochemical co-purification approach has successfully identified RNA-binding proteins with a particular role in regulating post-transcriptional expression of stress-activated mRNAs. Overall design: We performed 3 biologically independent 5PSeq experiments before stress (t0) and 30 minutes after osmotic stress (t 30).