Translational control plays an important role in the adaptive heat-shock response of Streptomyces coelicolor

Abstract

Stress-induced adaptations require multiple levels of regulation in all organisms to repair cellular damage. In the present study we evaluated the genome-wide transcriptional and translational changes following heat stress exposure in the soil-dwelling model actinomycete bacterium, Streptomyces coelicolor. The combined analysis revealed an unprecedented level of translational control of gene expression, deduced through polysome profiling, in addition to transcriptional changes. Our data show little correlation between the transcriptome and 'translatome'; while an obvious downward trend in genome wide transcription was observed, polysome associated transcripts following heat-shock showed an opposite upward trend. A handful of key protein players, including the major molecular chaperones and proteases were highly induced at both the transcriptional and translational level following heat-shock, a phenomenon known as 'potentiation'. Many other transcripts encoding cold-shock proteins, ABC-transporter systems, multiple transcription factors were more highly polysomeassociated following heat stress; interestingly, these protein families were not induced at the transcriptional level and therefore were not previously identified as part of the stress response. Thus, stress coping mechanisms at the level of gene expression in this bacterium go well beyond the induction of a relatively small number of molecular chaperones and proteases in order to ensure cellular survival at non-physiological temperatures.

A cold shock protein promotes high-temperature microbial growth through binding to diverse RNA species

“…Several proteins containing CSD show varied nucleic acid-binding activities that affect gene transcription, DNA replication, and DNA repair, while others interact with mRNA to affect translational efficiency 12,13,23,24 . Recently, the cold shock proteins have been highlighted the likely importance in adaptation to stress that were not previously considered to be part of the heat-shock stimulon in Streptomyces coelicolor 25 . Thus, we hypothesized that proteins containing CSD from thermophilic bacteria, which already show adaptability to high temperatures, might serve as updated stressresponse elements to improve high temperature tolerance of other microbes.…”

A major checkpoint for protein expression in Rhodobacter sphaeroides during heat stress response occurs at the level of translation

“…Moreover, at least some of these differences were attributed to an unknown mechanism, which caused the ribosomes to pause at the starting regions of open reading frames (ORFs) (Zhang et al ., 2017). Another recent study involving polysomal RNA analysis during heat shock on the model actinomycete bacterium, Streptomyces coelicolor , found ‘little correlation between the transcriptome and translatome’ and proposed an ‘unprecedented level of translational control of gene expression’ during stress (Bucca et al ., 2018).…”

Metagenome-wide measurement of protein synthesis in the human fecal microbiota using MetaRibo-Seq

“…This even extends to pathway-specific enzyme stoichiometry in which protein synthesis remains conserved as compensation for transcript abundance and architecture divergence across taxa17. Moreover, specific translational regulation has been extensively observed upon a variety of perturbations to bacteria 23,24,25,26,27,28,29 . For example, bacteria employ translational quality control and regulation of amino acid biosynthesis in response to amino acid stress 30 .…”