HSPC117 Is the Essential Subunit of a Human tRNA Splicing Ligase Complex

@article{Popow2011HSPC117IT,
  title={HSPC117 Is the Essential Subunit of a Human tRNA Splicing Ligase Complex},
  author={Johannes Popow and Markus Englert and Stefan Weitzer and Alexander Schleiffer and Beata Mierzwa and Karl Mechtler and Simon Trowitzsch and Cindy L Will and Reinhard L{\"u}hrmann and Dieter S{\"o}ll and Javier Martinez},
  journal={Science},
  year={2011},
  volume={331},
  pages={760 - 764}
}
The human enzyme that joins transfer RNA exons together is discovered. Splicing of mammalian precursor transfer RNA (tRNA) molecules involves two enzymatic steps. First, intron removal by the tRNA splicing endonuclease generates separate 5′ and 3′ exons. In animals, the second step predominantly entails direct exon ligation by an elusive RNA ligase. Using activity-guided purification of tRNA ligase from HeLa cell extracts, we identified HSPC117, a member of the UPF0027 (RtcB) family, as the… 

Molecular architecture of the human tRNA ligase complex

It is shown that the core of the human tRNA-LC is assembled from RTCB and the C-terminal alpha-helical regions of DDX1, CGI-99, and FAM98B, all of which are required for complex integrity.

Function of yeast and amphioxus tRNA ligase in IRE1alpha-dependent XBP1 mRNA splicing.

Eukaryotic tRNA splicing – one goal, two strategies, many players

Current understanding of eukaryotic tRNA splicing and the underlying enzyme machinery is summarized and a special focus lies on biochemically distinct strategies for exon-exon ligation in fungi versus metazoans.

RtcB, a Novel RNA Ligase, Can Catalyze tRNA Splicing and HAC1 mRNA Splicing in Vivo*

Escherichia coli RtcB is competent and sufficient for tRNA splicing in vivo by virtue of its ability to complement growth of yeast cells that lack the endogenous “healing/sealing-type” tRNA ligase Trl1 and is a bona fide RNA repair enzyme with broad physiological actions.

Reconstitution of the Human tRNA Splicing Endonuclease Complex: insight into the regulation of pre-tRNA cleavage

RNAi knockdown of the Drosophila CLP1 orthologue, cbc, promotes biogenesis of mature tRNAs and circularized tRNA introns (tricRNAs) in vivo, suggesting that CLP 1/cbc plays a regulatory role in tRNA splicing by serving as a negative modulator of the direct tRNA ligation pathway in animal cells.

Intron excision from precursor tRNA molecules in mammalian cells requires ATP hydrolysis and phosphorylation of tRNA-splicing endonuclease components.

The investigation of the biochemical requirements in pre-tRNA splicing is extended and it is found that β-γ-hydrolysable ATP is crucial for the productive generation of exon halves and evidence that phosphorylation of the TSEN complex components supports efficient pre- tRNA cleavage is provided.

Crystal structure of human archease, a key cofactor of tRNA splicing ligase complex.

INTRON AND RNA SPLICING IN ARCHAEA

The novel tertiary structure of the splicing endonuclease is solved, and it is revealed that the lineage-specific insertion of amino acid residues in the end onuclease expands the recognition of the substrate precursor RNA.

Metazoan tRNA introns generate stable circular RNAs in vivo

A class of abundant circular noncoding RNAs that are produced during metazoan tRNA splicing are discovered and an in vivo expression system for generating "designer" circular RNAs in human cells is developed.

Structural basis for the GTP specificity of the RNA kinase domain of fungal tRNA ligase

The 2.2 Å crystal structure of the kinase domain of Trl1 from the fungal pathogen Candida albicans with GDP and Mg2+ in the active site fortify the case for the Trl 1 kinase as an antifungal target.
...

References

SHOWING 1-10 OF 29 REFERENCES

Plant tRNA ligases are multifunctional enzymes that have diverged in sequence and substrate specificity from RNA ligases of other phylogenetic origins

Plant tRNA ligases are active on a variety of substrates in vitro and are capable of inter- and intramolecular RNA joining, so it is concluded that their role in vivo might comprise yet unknown essential functions besides their involvement in pre-tRNA splicing.

Conserved mechanism of tRNA splicing in eukaryotes.

It is demonstrated in this study the existence of a yeast tRNA ligase-like activity in HeLa cells, and the entire yeastlike tRNA splicing machinery is intact, arguing that the mechanism of t RNA splicing is conserved among eukaryotes.

Saccharomyces cerevisiae tRNA ligase. Purification of the protein and isolation of the structural gene.

The amino acid sequence of the amino-terminal end of the protein was determined, and this information was used to isolate the structural gene from a library of yeast DNA and it is proved that this DNA encodes the tRNA ligase protein.

Genetic and Biochemical Analysis of the Functional Domains of Yeast tRNA Ligase*

The results suggest that GTP is the physiological substrate and that the Trl1 kinase has a single NTP binding site of which the P-loop is a component.

Mutational Analysis of Bacteriophage T4 RNA Ligase 1

A shared evolutionary history and active site architecture in Rnl1 (a tRNA repair enzyme) and Trl1 ( a tRNA splicing enzyme) is infer and structure-activity relationships via conservative substitutions are determined viaconservative substitutions.

The human RNA kinase hClp1 is active on 3′ transfer RNA exons and short interfering RNAs

The physiological role of hClp1 is revealed as the RNA kinase that phosphorylates the 5′ end of the 3′ exon during human tRNA splicing, allowing the subsequent ligation of both exon halves by an unknown tRNA ligase.