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RNA-catalyzed evolution of catalytic RNA.

Nikolaos Papastavrou1, David P Horning1, Gerald F Joyce1

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Summary
This summary is machine-generated.

High-fidelity RNA polymerase ribozymes enable Darwinian evolution by accurately replicating functional RNA. Improved fidelity is crucial for maintaining genetic information in early life systems and laboratory evolution experiments.

Keywords:
RNA polymeraseRNA replicationdirected evolutionribozyme

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Area of Science:

  • Origin of Life Studies
  • Molecular Evolution
  • Biochemistry

Background:

  • Directed evolution has yielded RNA polymerase ribozymes capable of RNA replication.
  • Previous ribozyme versions lacked sufficient fidelity for sustained information propagation.
  • Hammerhead ribozymes are model systems for studying RNA-based evolution.

Purpose of the Study:

  • To assess the impact of RNA polymerase fidelity on Darwinian evolution of RNA.
  • To investigate the evolution of hammerhead ribozymes using high-fidelity replication.
  • To understand the role of replication fidelity in maintaining heritable information.

Main Methods:

  • Directed evolution of an RNA polymerase ribozyme for improved fidelity.
  • Parallel evolution experiments using low-fidelity and high-fidelity polymerases.
  • Deep sequencing to track sequence changes and fitness over evolutionary time.
  • Selection for RNA cleavage activity to drive evolution.

Main Results:

  • The high-fidelity polymerase successfully replicated hammerhead ribozymes, leading to evolved variants with increased fitness.
  • Low-fidelity replication resulted in loss of hammerhead functionality and sequence divergence.
  • Evolved hammerhead variants exhibited improved replicability, balancing a slight decrease in catalytic activity.
  • Deep sequencing revealed a progressive divergence of sequences correlating with increased fitness.

Conclusions:

  • High replication fidelity is essential for maintaining and evolving functional RNA in a Darwinian system.
  • Achieving high fidelity is a critical bottleneck for recreating RNA-based life in the laboratory.
  • This work provides insights into the potential evolutionary pathways of early RNA-based life.