Ribozyme-Catalyzed Transcription of an Active Ribozyme

  title={Ribozyme-Catalyzed Transcription of an Active Ribozyme},
  author={Aniela Wochner and James Attwater and Alan S Coulson and Philipp Holliger},
  pages={209 - 212}
A functional RNA has been synthesized by an RNA enzyme from mononucleotide building blocks. A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of replicating a primordial RNA “genome.” Here we describe the evolution and engineering of an RNA polymerase ribozyme capable of synthesizing RNAs of up to 95 nucleotides in length. To overcome its sequence dependence, we recombined traits evolved separately in different ribozyme lineages. This… 

RNA Synthesis by in Vitro Selected Ribozymes for Recreating an RNA World

This review focuses on three types of ribozymes that could have been involved in the synthesis of RNA, the core activity in the self-replication of RNA world organisms.

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.

An RNA polymerase ribozyme that synthesizes its own ancestor

The class I RNA polymerase ribozyme was evolved in vitro for the ability to synthesize functional ribozymes, resulting in the markedly improved ability to synthesisize complex RNAs using nucleoside 5′-triphosphate (NTP) substrates.

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 RNApolymerase 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 219 8C, an important stepping stone towards RNA self-replication.

A reverse transcriptase ribozyme

A highly evolved RNA polymerase ribozyme was found to also be capable of functioning as a reverse transcriptase, an activity that has never been demonstrated before for RNA. This activity is thought

Amplification of RNA by an RNA polymerase ribozyme

In vitro evolution is reported of an improved RNA polymerase ribozyme that is able to synthesize structured functional RNAs, including aptamers and ribozymes, and replicate short RNA sequences in a protein-free form of the PCR, ensuring the two prerequisites of Darwinian life can now be accomplished with RNA in the complete absence of proteins.

A ribozyme transcribed by a ribozyme

  • T. Bentin
  • Biology
    Artificial DNA, PNA & XNA
  • 2011
Recent work from the Holliger group at the Laboratory for Molecular Biology in Cambridge has provided synthetic ribozymes that just might foreshadow the future engineering of such self-replicative systems.

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.

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.

Crystal Structure of the Catalytic Core of an RNA-Polymerase Ribozyme

The structure of a ligase ribozyme suggests how RNA might be able to replicate itself and could be superimposed upon that of the protein enzyme to reveal analogous residues important for the catalytic joining of RNA moieties.

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.

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

An RNA molecule is described that catalyzes the type of polymerization needed for RNA replication, which 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.

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.

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.

Selection of an improved RNA polymerase ribozyme with superior extension and fidelity.

The isolation of an RNA polymerase ribozyme called B6.61 that exhibits superior extension and fidelity relative to its progenitor, the Round-18 polymerase, demonstrates the feasibility of evolving an artificial RNA replicase Ribozyme in the foreseeable future.

Characterization of the B6.61 polymerase ribozyme accessory domain.

This geometry suggests how the purine bulge in the polymerase replaces the P2 helix in the Class I ligase with a new structure that may facilitate the stabilization of incoming nucleotide triphosphates.

Directed evolution of nucleic acid enzymes.

  • G. F. Joyce
  • Biology, Chemistry
    Annual review of biochemistry
  • 2004
This review focuses on the development of nucleic acid enzymes starting from a population of random-sequence RNA or DNA molecules, and two especially well-studied categories of catalytic nucleic acids are considered: RNA enzymes that catalyze the template-directed ligation of RNA and DNA enzymes that Catalyst the cleavage of RNA.

In vitro selection of functional nucleic acids.

By selecting high-affinity and -specificity nucleic acid ligands for proteins, promising new therapeutic and diagnostic reagents have been identified and the existence of such RNA enzymes supports the notion that ribozymes could have directed a primitive metabolism before the evolution of protein synthesis.