Translation initiation factor IF2 contributes to ribosome assembly and maturation during cold adaptation

Brandi, Anna; Piersimoni, Lolita; Feto, Naser Aliye; Spurio, Roberto; Schmidt, Frank; Gualerzi, Claudio O.

doi:10.1093/nar/gkz188

Cited by 20 publications

(11 citation statements)

References 62 publications

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“…This idea is further bolstered by translational rescue observed upon the elevation of cellular concentrations of IFs (Figure 6A–C, 7A–B). Additionally, this also reiterates the recent reports of the close coupling between 30S maturation, translation initiation (89,90) and stress tolerance (91,92) in bacteria .…”

Section: Discussionsupporting

confidence: 86%

Ribosome assembly defects subvert initiation Factor3 mediated scrutiny of bona fide start signal

Sharma

Anand

2019

Nucleic Acids Research

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In bacteria, the assembly factors tightly orchestrate the maturation of ribosomes whose competency for protein synthesis is validated by translation machinery at various stages of translation cycle. However, what transpires to the quality control measures when the ribosomes are produced with assembly defects remains enigmatic. In Escherichia coli, we show that 30S ribosomes that harbour assembly defects due to the lack of assembly factors such as RbfA and KsgA display suboptimal initiation codon recognition and bypass the critical codon–anticodon proofreading steps during translation initiation. These premature ribosomes on entering the translation cycle compromise the fidelity of decoding that gives rise to errors during initiation and elongation. We show that the assembly defects compromise the binding of initiation factor 3 (IF3), which in turn appears to license the rapid transition of 30S (pre) initiation complex to 70S initiation complex by tempering the validation of codon–anticodon interaction during translation initiation. This suggests that the premature ribosomes harbouring the assembly defects subvert the IF3 mediated proofreading of cognate initiation codon to enter the translation cycle.

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Section: Discussionsupporting

confidence: 86%

Ribosome assembly defects subvert initiation Factor3 mediated scrutiny of bona fide start signal

Sharma

Anand

2019

Nucleic Acids Research

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“…In this connection, it should be stressed that IF2 and EF-Tu bind to overlapping ribosomal sites so that the dissociation or at least the displacement of IF2 from its ribosomal site is necessary to allow A-site binding of the aminoacyl-tRNA carried by the EF-Tu ternary complex. Unlike the late events of translation initiation, which do not seem to require IF2-dependent GTP hydrolysis, the cold-sensitive phenotype and the accumulation of ribosomal subunit precursors in the cells lacking the GTPase of IF2 indicate that this activity may play a role in assisting the protein chaperone activity of the factor during subunits assembly/maturation [53].…”

Section: Discussionmentioning

confidence: 99%

Disparate Phenotypes Resulting from Mutations of a Single Histidine in Switch II of Geobacillus stearothermophilus Translation Initiation Factor IF2

Tomšič

Smorlesi

Caserta

et al. 2020

IJMS

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The conserved Histidine 301 in switch II of Geobacillus stearothermophilus IF2 G2 domain was substituted with Ser, Gln, Arg, Leu and Tyr to generate mutants displaying different phenotypes. Overexpression of IF2H301S, IF2H301L and IF2H301Y in cells expressing wtIF2, unlike IF2H301Q and IF2H301R, caused a dominant lethal phenotype, inhibiting in vivo translation and drastically reducing cell viability. All mutants bound GTP but, except for IF2H301Q, were inactive in ribosome-dependent GTPase for different reasons. All mutants promoted 30S initiation complex (30S IC) formation with wild type (wt) efficiency but upon 30S IC association with the 50S subunit, the fMet-tRNA reacted with puromycin to different extents depending upon the IF2 mutant present in the complex (wtIF2 ≥ to IF2H301Q > IF2H301R >>> IF2H301S, IF2H301L and IF2H301Y) whereas only fMet-tRNA 30S-bound with IF2H301Q retained some ability to form initiation dipeptide fMet-Phe. Unlike wtIF2, all mutants, regardless of their ability to hydrolyze GTP, displayed higher affinity for the ribosome and failed to dissociate from the ribosomes upon 50S docking to 30S IC. We conclude that different amino acids substitutions of His301 cause different structural alterations of the factor, resulting in disparate phenotypes with no direct correlation existing between GTPase inactivation and IF2 failure to dissociate from ribosomes.

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“…The mutant also displayed a growth defect at low temperature. This growth defect at low temperature could be attributed to the aberrant ribosome biogenesis and assembly (Brandi et al, ; Herold, Nowotny, Dabbs, & Nierhaus, ; Kaczanowska & Ryden‐Aulin, ; VanBogelen & Neidhardt, ). However, to the best of our knowledge, the acid‐sensitive phenotype due to a defective L4 protein has not been previously reported.…”

Section: Discussionmentioning

confidence: 99%

Ribosomal protein L4 of Lactobacillus rhamnosus LRB alters resistance to macrolides and other antibiotics

Biswas

Keightley

Biswas

2020

Molecular Oral Microbiology

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Lactobacillus rhamnosus is an important lactic acid bacterium that is predominantly used as a probiotic supplement. This bacterium secretes immunomodulatory and antibacterial peptides that are necessary for the probiotic trait. This organism also occupies diverse ecological niches, such as gastrointestinal tracts and the oral cavity. Several studies have shown that L. rhamnosus is prone to spontaneous genome rearrangement irrespective of the ecological origins. We previously characterized an oral isolate of L. rhamnosus, LRB, which is genetically closely related to the widely used probiotic strain L. rhamnosus LGG. In this study, we isolated a nontargeted mutant that was particularly sensitive to acid stress. Using next generation sequencing, we further mapped the putative mutations in the genome and found that the mutant had acquired a deletion of 75 base pairs in the rplD gene that encodes the large ribosomal subunit L4. The mutant had a growth defect at 37°C and at ambient temperature. Further antibiotic sensitivity analyses indicated that the mutant is relatively more resistant to erythromycin and chloramphenicol; two antibiotics that target the 50S subunit. In contrast, the mutant was more sensitive to tetracycline, which targets the 30S subunit. Thus, it appears that nontargeted mutations could significantly alter the antibiotic resistance profile of L. rhamnosus. Our study raises concern that probiotic use of L. rhamnosus should be carefully monitored to avoid unintended consequences.

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Translation initiation factor IF2 contributes to ribosome assembly and maturation during cold adaptation

Cited by 20 publications

References 62 publications

Ribosome assembly defects subvert initiation Factor3 mediated scrutiny of bona fide start signal

Ribosome assembly defects subvert initiation Factor3 mediated scrutiny of bona fide start signal

Disparate Phenotypes Resulting from Mutations of a Single Histidine in Switch II of Geobacillus stearothermophilus Translation Initiation Factor IF2

Ribosomal protein L4 of Lactobacillus rhamnosus LRB alters resistance to macrolides and other antibiotics

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