The canonical ribosome cycle in bacteria consists of initiation, elongation, termination, and recycling stages. After the recycling stage, initiation factor 3 (IF3) stabilizes ribosomal dissociation by binding to 30S subunits for the next round of translation. On the other hand, during the stationary growth phase, it has been elucidated that Escherichia coli ribosomes are dimerized (100S ribosome formation) by binding ribosome modulation factor (RMF) and hibernation promoting factor (HPF), leading to a hibernation stage. This indicates that 100S ribosomes are formed after these factors are scrambled for ribosomes concomitantly with transition from the log phase to the stationary phase. In this study, to elucidate the ribosomal events before 100S ribosome formation, the relationships between protein factors (RMF and HPF) involved in 100S ribosome formation and IF3 involved in initiation complex formation were examined. As a result of in vitro assays, it was found that ribosomal dissociation activity by IF3 fell, and that ribosomal dimerization activity by RMF and HPF was elevated more when using stationary-phase ribosomes than when using log-phase ribosomes. This suggests that ribosomes change into forms which are hard to bind with IF3 and easy to form 100S ribosomes by RMF and HPF concomitantly with transition from the log phase to the stationary phase.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/j.1365-2443.2008.01272.x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Staphylococcal exoribonuclease YhaM destabilizes ribosomes by targeting the mRNA of a hibernation factor.
Nucleic Acids Res
August 2024
Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, 320 E Superior St, Chicago, IL 60611, USA.
The hibernation-promoting factor (Hpf) in Staphylococcus aureus binds to 70S ribosomes and induces the formation of the 100S complex (70S dimer), leading to translational avoidance and occlusion of ribosomes from RNase R-mediated degradation. Here, we show that the 3'-5' exoribonuclease YhaM plays a previously unrecognized role in modulating ribosome stability. Unlike RNase R, which directly degrades the 16S rRNA of ribosomes in S.
View Article and Find Full Text PDFThe hibernation promoting factor of Betaproteobacteria Comamonas testosteroni cannot induce 100S ribosome formation but stabilizes 70S ribosomal particles.
Genes Cells
August 2024
Biological Information Research, Yoshida Biological Laboratory Inc., Yoshida Biological Laboratory, Kyoto, Japan.
Bacteria use several means to survive under stress conditions such as nutrient depletion. One such response is the formation of hibernating 100S ribosomes, which are translationally inactive 70S dimers. In Gammaproteobacteria (Enterobacterales), 100S ribosome formation requires ribosome modulation factor (RMF) and short hibernation promoting factor (HPF), whereas it is mediated by only long HPF in the majority of bacteria.
View Article and Find Full Text PDFCryo- EM structure of the mycobacterial 70S ribosome in complex with ribosome hibernation promotion factor RafH.
Nat Commun
January 2024
Structural Biology & Translation Regulation Laboratory, UNESCO-DBT, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India.
Ribosome hibernation is a key survival strategy bacteria adopt under environmental stress, where a protein, hibernation promotion factor (HPF), transitorily inactivates the ribosome. Mycobacterium tuberculosis encounters hypoxia (low oxygen) as a major stress in the host macrophages, and upregulates the expression of RafH protein, which is crucial for its survival. The RafH, a dual domain HPF, an orthologue of bacterial long HPF (HPF), hibernates ribosome in 70S monosome form, whereas in other bacteria, the HPF induces 70S ribosome dimerization and hibernates its ribosome in 100S disome form.
View Article and Find Full Text PDFCryoEM reveals that ribosomes in microsporidian spores are locked in a dimeric hibernating state.
Nat Microbiol
October 2023
Living Systems Institute, University of Exeter, Exeter, UK.
Translational control is an essential process for the cell to adapt to varying physiological or environmental conditions. To survive adverse conditions such as low nutrient levels, translation can be shut down almost entirely by inhibiting ribosomal function. Here we investigated eukaryotic hibernating ribosomes from the microsporidian parasite Spraguea lophii in situ by a combination of electron cryo-tomography and single-particle electron cryo-microscopy.
View Article and Find Full Text PDFMetal-Responsive Transcription Factors Co-Regulate Anti-Sigma Factor (Rsd) and Ribosome Dimerization Factor Expression.
Int J Mol Sci
March 2023
Micro-Nano Technology Research Center, Hosei University, Koganei 184-0003, Tokyo, Japan.
Bacteria exposed to stress survive by regulating the expression of several genes at the transcriptional and translational levels. For instance, in , when growth is arrested in response to stress, such as nutrient starvation, the anti-sigma factor Rsd is expressed to inactivate the global regulator RpoD and activate the sigma factor RpoS. However, ribosome modulation factor (RMF) expressed in response to growth arrest binds to 70S ribosomes to form inactive 100S ribosomes and inhibit translational activity.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!