Effective extraction of polyribosomes exposes gene expression strategies in primary astrocytes.

Abstract

Regulation of mRNA translation in astrocytes gains a growing interest. However, until now, successful ribosome profiling of primary astrocytes has not been reported. Here, we optimized the standard 'polysome profiling' method and generated an effective protocol for polyribosome extraction, which enabled genome-wide assessment of mRNA translation dynamics along the process of astrocyte activation. Transcriptome (RNAseq) and translatome (Riboseq) data generated at 0, 24and 48 hafter cytokines treatment, revealed dynamic genome-wide changes in the expression level of ∼12000 genes. The data clarify whether a change in protein synthesis rateresults from a change in mRNA levelor translation efficiency per se. It exhibitdifferent expression strategies, based on changes in mRNA abundance and/or translation efficiency, which arespecifically assigned to gene subsets depending on their function. Moreover, the study raises an important take-home message related to the possible presence of 'difficult to extract' polyribosome sub-groups, in all cell types, thus illuminating the impact of ribosomes extraction methodology on experiments addressing translation regulation.