RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension

  title={RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension},
  author={Wendy K. Johnston and Peter J. Unrau and Michael S. Lawrence and Margaret E. Glasner and David P. Bartel},
  pages={1319 - 1325}
The RNA world hypothesis regarding the early evolution of life relies on the premise that some RNA sequences can catalyze RNA replication. In support of this conjecture, we describe here an RNA molecule that catalyzes the type of polymerization needed for RNA replication. The ribozyme uses nucleoside triphosphates and the coding information of an RNA template to extend an RNA primer by the successive addition of up to 14 nucleotides—more than a complete turn of an RNA helix. Its polymerization… 

Polymerase ribozyme efficiency increased by G/T-rich DNA oligonucleotides.

The results indicate that these DNA sequences function by establishing many weak and nonspecific base-pairing interactions to the single-stranded portion of the template, which could have had important functions in an RNA world.

Processivity of ribozyme-catalyzed RNA polymerization.

A method of measuring polymerase processivity that is particularly useful in the case of an inefficient polymerase is developed, allowing it to be demonstrated that the polymerase ribozyme, despite its inefficiency, is partially processive.

Arginine Cofactors on the Polymerase Ribozyme

Results suggest that the existing polymerase ribozyme is not well suited to using an arginine cofactor, because this is the amino acid most adept to interact with RNA.

Ribozyme-catalysed RNA synthesis using triplet building blocks

This work reports RNA-catalysed RNA synthesis on structured templates when using trinucleotide triphosphates (triplets) as substrates, catalysed by a general and accurate triplet polymerase ribozyme that emerged from in vitro evolution as a mutualistic RNA heterodimer.

In-ice evolution of RNA polymerase ribozyme activity.

In vitro evolution of catalysts directly in the RNA-stabilizing medium of water ice yielded RNA polymerase ribozymes specifically adapted to sub-zero temperatures and able to synthesize RNA in ices at temperatures as low as -19 °C, an important stepping stone towards RNA self-replication.

Non-Enzymatic Assembly of a Minimized RNA Polymerase Ribozyme

The results provide support for the possibility that complex RNA structures could have emerged from pools of activated RNA oligomers and outlines a path for the transition from non-enzymatic/chemical to enzymatic RNA replication.

ligation of random RNA oligomers The dawn of the RNA World : Toward functional complexity through

A stepwise model of ligation-based, modular evolution is built up that could pave the way to the emergence of a ribozyme with RNA replicase activity, step at which information-driven Darwinian evolution would be driven.

Ribozyme-Catalyzed Transcription of an Active Ribozyme

The evolution and engineering of an RNA polymerase ribozyme capable of synthesizing RNAs of up to 95 nucleotides in length is described, and the accurate synthesis of an enzymatically active RNA, a hammerhead endonuclease ribo enzyme is demonstrated.



RNA-catalysed RNA polymerization using nucleoside triphosphates

An RNA is described that synthesizes RNA using the same reaction as that employed by protein enzymes that catalyse RNA polymerization, and shows marked template fidelity.

A model for the RNA-catalyzed replication of RNA.

  • T. Cech
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1986
It seems possible that RNA catalysts might have played a part in prebiotic nucleic acid replication, prior to the availability of useful proteins, if the RNA enzyme could use another copy of itself as a template, RNA self-replication could be achieved.

Recognition of nucleoside triphosphates during RNA-catalyzed primer extension.

The polymerase Ribozyme, derived from an efficient RNA ligase ribo enzyme, can achieve the very fast k(cat) of the parent ribozyme when the substrate of the polymerase is replaced by an extended substrate (pppGGA), in which the GA dinucleotide extension corresponds to the second and third nucleotides of the ligase.

A multisubunit ribozyme that is a catalyst of and template for complementary strand RNA synthesis.

Results suggest that prebiotically synthesized oligonucleotides might have been able to assemble into a complex capable of self-replication.

RNA-catalysed nucleotide synthesis

The finding that RNA can catalyse this type of reaction, which is modelled after pyrimidine synthesis in contemporary metabolism, supports the idea of an RNA world that included nucleotide synthesis and other metabolic pathways mediated by ribozymes.

Constructing an RNA world.

Isolation of new ribozymes from a large pool of random sequences [see comment].

An iterative in vitro selection procedure was used to isolate a new class of catalytic RNAs (ribozymes) from a large pool of random-sequence RNA molecules, leading to improvement of the average ligation activity and the emergence of ribozymes with reaction rates 7 million times faster than the uncatalyzed reaction rate.

Structurally complex and highly active RNA ligases derived from random RNA sequences.

Seven families of RNA ligases, previously isolated from random RNA sequences, fall into three classes on the basis of secondary structure and regiospecificity of ligation, which implies the existence of a large number of distinct RNA structures of equivalent complexity and activity.