Maturation Pathways for E. coli tRNA Precursors: A Random Multienzyme Process In Vivo

Li, Zhongwei; Deutscher, Murray P.

doi:10.1016/s0092-8674(00)80123-3

Cited by 174 publications

(207 citation statements)

References 26 publications

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“…Processing of the 39 terminus of tRNAs in eukaryotes involves an endonucleolytic cleavage (Dubrovsky et al, 2004;Mörl & Marchfelder, 2001;Schurer et al, 2001), with exonucleolytic processing as an alternative pathway. In Escherichia coli, different endo-and exoRNases participate in different combinations as needed for the particular arrangement of tRNA genes in operons (Li & Deutscher, 1996;Li et al, 2002;Ow & Kushner, 2002;Mohanty & Kushner, 2007. In Mycoplasma genitalium, the only identified exoRNase is RNase R, which is suggested to process the 39 end of tRNAs and to also have degradative functions (Lalonde et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Characterization of tRNACys processing in a conditional Bacillus subtilis CCase mutant reveals the participation of RNase R in its quality control

et al. 2010

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We generated a conditional CCase mutant of Bacillus subtilis to explore the participation in vivo of the tRNA nucleotidyltransferase (CCA transferase or CCase) in the maturation of the singlecopy tRNA Cys , which lacks an encoded CCA 39 end. We observed that shorter tRNA Cys species, presumably lacking CCA, only accumulated when the inducible Pspac : cca was introduced into an rnr mutant strain, but not in combination with pnp. We sequenced the tRNA 39 ends produced in the various mutant tRNA Cys species to detect maturation and decay intermediates and observed that decay of the tRNA Cys occurs through the addition of poly(A) or heteropolymeric tails. A few clones corresponding to full-size tRNAs contained either CCA or other C and/or A sequences, suggesting that these are substrates for repair and/or decay. We also observed editing of tRNA Cys at position 21, which seems to occur preferentially in mature tRNAs. Altogether, our results provide in vivo evidence for the participation of the B. subtilis cca gene product in the maturation of tRNAs lacking CCA. We also suggest that RNase R exoRNase in B. subtilis participates in the quality control of tRNA.

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Section: Introductionmentioning

confidence: 99%

Characterization of tRNACys processing in a conditional Bacillus subtilis CCase mutant reveals the participation of RNase R in its quality control

et al. 2010

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“…The best characterized function of this enzyme is trimming of tRNA precursors at their 3¢ ends [20,21]. RNase PH homologs are small single domain proteins that are distributed among all three primary kingdoms.…”

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confidence: 99%

The PNPase, exosome and RNA helicases as the building components of evolutionarily-conserved RNA degradation machines

2007

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The structure and function of polynucleotide phosphorylase (PNPase) and the exosome, as well as their associated RNA-helicases proteins, are described in the light of recent studies. The picture raised is of an evolutionarily conserved RNA-degradation machine which exonucleolytically degrades RNA from 3¢ to 5¢. In prokaryotes and in eukaryotic organelles, a trimeric complex of PNPase forms a circular doughnutshaped structure, in which the phosphorolysis catalytic sites are buried inside the barrel-shaped complex, while the RNA binding domains create a pore where RNA enters, reminiscent of the protein degrading complex, the proteasome. In some archaea and in the eukaryotes, several different proteins form a similar circle-shaped complex, the exosome, that is responsible for 3¢ to 5¢ exonucleolytic degradation of RNA as part of the processing, quality control, and general RNA degradation process. Both PNPase in prokaryotes and the exosome in eukaryotes are found in association with protein complexes that notably include RNA helicase.

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“…Whereas these enzymes are known to play important roles in many aspects of RNA metabolism (2,3), their participation in RNA quality control processes has not been elucidated. It is known that PNPase and RNase II are required to remove mRNA fragments that are generated during the course of mRNA decay (4).…”

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confidence: 99%

Quality control of ribosomal RNA mediated by polynucleotide phosphorylase and RNase R

Cheng

Deutscher

2003

Proc. Natl. Acad. Sci. U.S.A.

190

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Despite their overall accuracy, errors in macromolecular processes, such as rRNA synthesis and ribosome assembly, inevitably occur. However, whether these errors are remediated and how this might be accomplished is not known. In previous work, we showed that a double mutant strain lacking both polynucleotide phosphorylase (PNPase) and RNase R activities is inviable. In the course of examining the molecular basis for this phenotype, we found that shifting a temperature-sensitive mutant strain to 42°C led to cessation of growth and loss of cell viability. Northern analysis of RNA isolated from such cells after the temperature shift revealed that fragments of 16S and 23S rRNA accumulated to a high level, and that the amount of ribosomes and ribosomal subunits decreased due to defects in ribosome assembly. rRNA fragments were not detected at 31°C or when single mutant strains were grown at 42°C. Pulse-chase analysis showed that the rRNA fragments appeared within 5 min at 42°C, and that they accumulated before the loss of cell viability. The data are consistent with a model in which PNPase and RNase R mediate a previously unknown quality control process that normally removes defective rRNAs as soon as they are generated. In the absence of these RNases, rRNA fragments accumulate, leading to interference with ribosome maturation and ultimately to cell death.

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Maturation Pathways for E. coli tRNA Precursors: A Random Multienzyme Process In Vivo

Cited by 174 publications

References 26 publications

Characterization of tRNACys processing in a conditional Bacillus subtilis CCase mutant reveals the participation of RNase R in its quality control

Characterization of tRNACys processing in a conditional Bacillus subtilis CCase mutant reveals the participation of RNase R in its quality control

The PNPase, exosome and RNA helicases as the building components of evolutionarily-conserved RNA degradation machines

Quality control of ribosomal RNA mediated by polynucleotide phosphorylase and RNase R

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