GSE200491
Ribosome profiling and RNA-seq of an acute glucose starvation timecourse and 5 day growth course in S. cerevisiae
Ribosome profiling provides an opportunity to not only assess how the relative abundance of ribosome association with mRNAs changes in different conditions, but to look more closely at where along mRNAs those ribosomes bind. Here, we used ribosome profiling to calculate the ribosome polarity scores and changes in ribosome footprint read density in both aggregate and gene-specific ways. We profiled a time course of acute glucose starvation followed by glucose readdition and a multi-day growth course through the diauxic shift into stationary phase. We found that ribosome polarity became positive in postdiauxic shift conditions relative to log phase. In acute starvation, polarity shifted positive at our earliest time points but did not continue to do so at later time points. This is consistent with a read density analysis which demonstrated increased density on the 3' half of genes after glucose starvation. Additionally, we performed ribosome profiling in samples that had glucose added back following acute starvation and observed a wave of new ribosome movement near the start codon and approximately 2,000 nucleotides downstream on open reading frames after one and five minutes of readdition, respectively. Our ribosome profiling analysis suggested that elongation slows during starvation which leads to a buildup of ribosomes on the 3' halves of mRNAs. Further, it also indicated ribosomes previously built up can resume translation upon glucose readdition. We used reporter assays to corroborate these findings in vivo. Together, these results demonstrate how yeast regulate translation in response to glucose starvation. Overall design: mRNA and ribosome occupancy profiles of S. cerevisiae in actue glucose starvation, glucose readdition, and mutli-day growth conditions