Portability and fidelity of RNA-repair systems Journal Article


Authors: Schwer, B.; Sawaya, R.; Ho, C. K.; Shuman, S.
Article Title: Portability and fidelity of RNA-repair systems
Abstract: Yeast tRNA ligase (Trl1) is an essential enzyme that converts cleaved tRNA half-molecules into spliced tRNAs containing a 2′-PO4, 3′-5′ phosphodiester at the splice junction. Trl1 also catalyzes splicing of HAC1 mRNA during the unfolded protein response. Trl1 performs three reactions: the 2′,3′-cyclic phosphate of the proximal RNA fragment is hydrolyzed to a 3′-OH, 2′-PO4 by a cyclic phosphodiesterase; the 5′-OH of the distal RNA fragment is phosphorylated by a GTP-dependent polynucleotide kinase; and the 3′-OH, 2′-PO 4, and 5′-PO4 ends are then sealed by an ATP-dependent RNA ligase. The removal of the 2′-PO4 at the splice junction is catalyzed by the essential enzyme Tpt1, which transfers the RNA 2′-PO4 to NAD+ to form ADP-ribose 1″-2″-cyclic phosphate. Here, we show that the bacteriophage T4 enzymes RNA ligase 1 and polynucleotide kinase/phosphatase can fulfill the tRNA and HAC1 mRNA splicing functions of yeast Trl1 in vivo and bypass the requirement for Tpt1. These results attest to the portability of RNA-repair systems, notwithstanding the significant differences in the specificities, mechanisms, and reaction intermediates of the individual yeast and T4 enzymes responsible for the RNA healing and sealing steps. We surmise that Tpt1 and its unique metabolite ADP-ribose 1″-2″-cyclic phosphate do not play essential roles in yeast independent of the tRNA-splicing reaction. Our finding that one-sixth of spliced HAC1 mRNAs in yeast cells containing the T4 RNA-repair system suffered deletion of a single nucleotide at the 3′ end of the splice-donor site suggests a model whereby the yeast RNA-repair system evolved a requirement for the 2′-PO4 for RNA ligation to suppress inappropriate RNA recombination.
Keywords: promoter region; nonhuman; polymerase chain reaction; gene expression; genetic transcription; rna; amino acid sequence; molecular sequence data; kinetics; messenger rna; saccharomyces cerevisiae; rna, messenger; nucleotide sequence; plasmid; base sequence; yeast; dna primers; adenosine triphosphate; transfer rna; rna, transfer; guanosine triphosphate; polynucleotide 5' hydroxyl kinase; rna ligase (atp); rna splicing; complementary dna; dna fragment; rna ligase; restriction mapping; protein denaturation; priority journal; article; rna recombination; genetic processes
Journal Title: Proceedings of the National Academy of Sciences of the United States of America
Volume: 101
Issue: 9
ISSN: 0027-8424
Publisher: National Academy of Sciences  
Date Published: 2004-03-02
Start Page: 2788
End Page: 2793
Language: English
DOI: 10.1073/pnas.0305859101
PROVIDER: scopus
PUBMED: 14973195
PMCID: PMC365698
DOI/URL:
Notes: Proc. Natl. Acad. Sci. U. S. A. -- Cited By (since 1996):36 -- Export Date: 16 June 2014 -- CODEN: PNASA -- Source: Scopus
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  1. Chong-Kiong Ho
    33 Ho
  2. Stewart H Shuman
    546 Shuman