An mRNA Is Capped by a 2', 5' Lariat Catalyzed by a Group I-Like Ribozyme

@article{Nielsen2005AnMI,
  title={An mRNA Is Capped by a 2', 5' Lariat Catalyzed by a Group I-Like Ribozyme},
  author={Henrik Nielsen and Eric Westhof and Steinar Daae Johansen},
  journal={Science},
  year={2005},
  volume={309},
  pages={1584 - 1587}
}
Twin-ribozyme introns are formed by two ribozymes belonging to the group I family and occur in some ribosomal RNA transcripts. The group I-like ribozyme, GIR1, liberates the 5′ end of a homing endonuclease messenger RNA in the slime mold Didymium iridis. We demonstrate that this cleavage occurs by a transesterification reaction with the joining of the first and the third nucleotide of the messenger by a 2′,5′-phosphodiester linkage. Thus, a group I-like ribozyme catalyzes an RNA branching… 

A conformational switch in the DiGIR1 ribozyme involved in release and folding of the downstream I-DirI mRNA.

The role of HEG P1 in GIR1 branching is reminiscent of that of hairpin P-1 in splicing of the Tetrahymena rRNA group I intron and illustrates a general principle in RNA-directed RNA processing.

A new RNA branching activity: the GIR1 ribozyme.

Speciation of a group I intron into a lariat capping ribozyme

The crystal structures of the precleavage and postcleavage LC ribozymes are described, which suggest that structural features inherited from group I Ribozymes have undergone speciation due to profound changes in molecular selection pressure, ultimately giving rise to an original branching ribozyme family.

cis-Acting 5' hammerhead ribozyme optimization for in vitro transcription of highly structured RNAs.

This work presents a method in which incorporation of a full-length hammerhead ribo enzyme with a specific tertiary interaction prevents alternative folding with the lariat capping GIR1 ribozyme and enables complete cleavage in the course of the transcription.

Molecular characterization of a new member of the lariat capping twin-ribozyme introns

The discovery of a twin-ribozyme intron in a member of Heterolobosea expands the distribution pattern of LC ribozymes and identifies a putative regulatory RNA element (AP2.1) in the Allovahlkampfia LC ribozyme that involves homing endonuclease mRNA coding sequences as an important structural component.

Group I intron ribozymes.

This chapter provides a strategy and protocols for initial characterization of new group I intron ribozymes and associated elements found within group I introns.

Lariat capping as a tool to manipulate the 5' end of individual yeast mRNA species in vivo.

This study has used the lariat capping ribozyme from the myxomycete Didymium to replace the mRNA m7G cap of a single reporter mRNA species with a tiny lariat in which the first and the third nucleotide are joined by a 2', 5' phosphodiester bond, consistent with a key role for the m8G cap in mRNA turnover.

Contributions to the study of the architecture and evolution of ribozymes

The pk-turn, a new RNA motif related to k-turns that allow for the formation of a bend of 60° between stems P16 and P17 from the bacterial RNaseP, is identified.

snRNAs as the catalysts of pre-mRNA splicing.

  • S. Valadkhan
  • Biology, Chemistry
    Current opinion in chemical biology
  • 2005

Use of a Lariat Capping Ribozyme to Study Cap Function In Vivo.

This chapter presents protocols to validate the presence of the lariat cap and measure the efficiency of in vivo cleavage by the Lariat capping ribozyme.
...

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