In all organisms, proteins are synthesized by ribosomes, large RNA-based enzymes that use aminoacyl- tRNA substrates to translate messenger RNA. In recent years, tremendous progress has been made in elucidating the structure of the ribosome in the absence and presence of substrates and various translation factors. Despite this wealth of structural information, several important questions about the molecular mechanisms of translation remain open. Furthermore, there exist highly conserved protein factors known to interact with the ribosome whose roles in the cell remain unclear. The long-term goal of my laboratory is to fill these gaps in knowledge.
Aim 1. Over the past several years, we have been studying mutations in the RNA component (16S rRNA) of the small (30S) subunit that promote miscoding. We found that mutation G299A on the solvent side of the 30S subunit acts by disrupting intersubunit bridge B8, which lies 80 angstroms away. Experiments of Aim 1 will determine which other fidelity mutations (ribosomal ambiguity or ram, error-promoting; restrictive or res, error-reducing) act by allosterically altering B8 and whether codon-anticodon interaction is coupled to B8 disruption. This work will shed light on the conformational dynamics of the subunit that govern the decoding process.
Aim 2. In all cells, ribosome assembly / maturation is monitored by quality control mechanisms. These mechanisms are complex and remain incompletely understood. Our recent work on the conserved translational GTPase LepA suggests that the factor contributes to translation initiation, either directly or indirectly. We hypothesize that LepA plays a role in ribosome assembly / maturation, and subunits formed in its absence are functional but defective in initiation. Experiments of Aim 2 will investigate this hypothesis, and may elucidate the physiological role of LepA. Ribosomes are a main target of antibiotics, and defects in translation are associated with a growing number of inherited human diseases and cancers. Insight gained by this project may lead to the development of novel antimicrobial drugs and/or treatments for one or more hereditary diseases.

Public Health Relevance

One of the largest challenges facing modern medicine is the emergence of antibiotic resistance, and many classes of medically useful antibiotics target the ribosome. Defects in protein synthesis have been attributed to many inherited human diseases, and a growing body of evidence suggests that alteration in ribosome biogenesis and/or activity plays an important role in the development of several cancers. Insight gained from this project may (1) aid efforts to develop novel antibiotics and/or therapy regimes to combat pathogens with multiple-drug resistance and (2) contribute to the treatment and/or prevention of one or more hereditary diseases and/or cancers.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM072528-12
Application #
9188813
Study Section
Molecular Genetics A Study Section (MGA)
Program Officer
Bender, Michael T
Project Start
2005-04-01
Project End
2018-11-30
Budget Start
2016-12-01
Budget End
2017-11-30
Support Year
12
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Ohio State University
Department
Microbiology/Immun/Virology
Type
Schools of Arts and Sciences
DUNS #
832127323
City
Columbus
State
OH
Country
United States
Zip Code
43210
Dai, Xiongfeng; Zhu, Manlu; Warren, Mya et al. (2018) Slowdown of Translational Elongation in Escherichia coli under Hyperosmotic Stress. MBio 9:
Gibbs, Michelle R; Fredrick, Kurt (2018) Roles of elusive translational GTPases come to light and inform on the process of ribosome biogenesis in bacteria. Mol Microbiol 107:445-454
Ying, Lanqing; Zhu, Hongkun; Shoji, Shinichiro et al. (2018) Roles of specific aminoglycoside-ribosome interactions in the inhibition of translation. RNA :
Hoffer, Eric D; Maehigashi, Tatsuya; Fredrick, Kurt et al. (2018) Ribosomal ambiguity (ram) mutations promote the open (off) to closed (on) transition and thereby increase miscoding. Nucleic Acids Res :
Chen, Menglin; Fredrick, Kurt (2018) Measures of single- versus multiple-round translation argue against a mechanism to ensure coupling of transcription and translation. Proc Natl Acad Sci U S A 115:10774-10779
Vo, My-Nuong; Terrey, Markus; Lee, Jeong Woong et al. (2018) ANKRD16 prevents neuron loss caused by an editing-defective tRNA synthetase. Nature 557:510-515
Gibbs, Michelle R; Moon, Kyung-Mee; Chen, Menglin et al. (2017) Conserved GTPase LepA (Elongation Factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome. Proc Natl Acad Sci U S A 114:980-985
Fleming, Ian M C; Paris, Zden?k; Gaston, Kirk W et al. (2016) A tRNA methyltransferase paralog is important for ribosome stability and cell division in Trypanosoma brucei. Sci Rep 6:21438
Dai, Xiongfeng; Zhu, Manlu; Warren, Mya et al. (2016) Reduction of translating ribosomes enables Escherichia coli to maintain elongation rates during slow growth. Nat Microbiol 2:16231
Liu, Qi; Fredrick, Kurt (2016) Intersubunit Bridges of the Bacterial Ribosome. J Mol Biol 428:2146-64

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