Evaluating the Impact of gRNA SNPs in CasRx Activity for Reducing Viral RNA in HCoV-OC43

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Updated: Sep 6, 2025

Overexpressing Long Noncoding RNAs Using Gene-activating CRISPR
13:04

Overexpressing Long Noncoding RNAs Using Gene-activating CRISPR

Published on: March 1, 2019

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Cathryn Michelle Mayes1,2, Joshua Santarpia2

  • 1Sandia National Laboratories, Albuquerque, NM 87123, USA.

Cells
|June 24, 2022
PubMed

Insights

This study demonstrates a pan-coronavirus CRISPR system targeting essential viral genes. The CasRx effector tolerates up to three mismatches in guide RNAs, showing potential for broad-spectrum coronavirus detection and inhibition.

Area of Science:

  • Molecular Biology
  • Virology
  • Biotechnology

Background:

  • Coronaviruses share essential, conserved genes critical for replication.
  • Targeting these conserved regions offers a strategy for broad-spectrum antiviral approaches.
  • CRISPR-Cas systems show promise for precise nucleic acid manipulation.

Purpose of the Study:

  • To develop a proof-of-concept for a pan-coronavirus CRISPR effector system.
  • To design cross-reactive CRISPR targets within essential human coronavirus genes.
  • To evaluate the efficacy and mismatch tolerance of the CasRx effector.

Main Methods:

  • Designed CRISPR targets for conserved RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) genes across human coronaviruses (HCoV).
  • Utilized sequencing alignment to identify highly conserved regions for guide RNA (gRNA) design.
  • Tested CasRx (a Cas13d effector) efficacy using RT-qPCR with engineered gRNAs containing mismatches against HCoV-OC43.

Main Results:

  • CRISPR targets were successfully designed for conserved HCoV genes.
  • CasRx demonstrated nuclease activity against HCoV-OC43 viral RNA.
  • The CasRx effector tolerated up to three mismatches in gRNA sequences while retaining activity.

Conclusions:

  • A pan-coronavirus CRISPR effector system is feasible by targeting conserved essential genes.
  • CasRx exhibits significant tolerance to guide RNA mismatches, enabling broader reactivity.
  • Further evaluation of off-target effects is crucial for safe and effective CRISPR applications with mismatched gRNAs.
Keywords:
CRISPRCasRxHCoV-OC43homologyhuman coronavirusesoff-target effects

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