Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris

ABSTRACT In this work, we developed a plasmid‐based CRISPR‐Cas9 strategy for editing Lactococcus cremoris, which allows easy generation of plasmid‐free strains with the desired modification. We constructed versatile shuttle vectors based on the theta‐type pAMβ1 promiscuous replicon and p15A ori, exp...

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Main Authors: Javier Nicolás Garay‐Novillo, José Ángel Ruiz‐Masó, Gloria delSolar, José Luis Barra
Format: Article
Language:English
Published: Wiley 2024-12-01
Series:Microbial Biotechnology
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Online Access:https://doi.org/10.1111/1751-7915.70060
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author Javier Nicolás Garay‐Novillo
José Ángel Ruiz‐Masó
Gloria delSolar
José Luis Barra
author_facet Javier Nicolás Garay‐Novillo
José Ángel Ruiz‐Masó
Gloria delSolar
José Luis Barra
author_sort Javier Nicolás Garay‐Novillo
collection DOAJ
description ABSTRACT In this work, we developed a plasmid‐based CRISPR‐Cas9 strategy for editing Lactococcus cremoris, which allows easy generation of plasmid‐free strains with the desired modification. We constructed versatile shuttle vectors based on the theta‐type pAMβ1 promiscuous replicon and p15A ori, expressing both the Cas9 nuclease gene (under pH‐regulated promoters derived from P170) and a single‐guide RNA for specific targeting (under a strong constitutive promoter). The vectors designed for plasmid targeting were very effective for low‐ and high‐copy‐number plasmid curing in L. cremoris, and their targeting efficiency was shown to be tunable by regulating cas9 expression. For chromosome editing, we implemented a host‐independent method that enhances double‐homologous recombination events using plasmids expressing the genes encoding λRed‐phage Redβ recombinase and Escherichia coli single‐stranded DNA binding protein (EcSSB). By coupling either the endogenous recombination machinery or the Redβ‐EcSSB‐assisted recombination system with our novel chromosome‐targeting CRISPR‐Cas9 plasmids, we efficiently generated and selected thousands of gene‐edited cells. Examination of the impact of the constructed CRISPR‐Cas9 vectors on host fitness revealed no Cas9‐associated toxicity, and, remarkably, these vectors exhibited a very high loss rate when growing the bacterial host cells in the absence of selective pressure.
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spelling doaj-art-b00902a293864cb6a10fa149dac2ef652025-08-20T02:50:47ZengWileyMicrobial Biotechnology1751-79152024-12-011712n/an/a10.1111/1751-7915.70060Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremorisJavier Nicolás Garay‐Novillo0José Ángel Ruiz‐Masó1Gloria delSolar2José Luis Barra3Departamento de Química Biológica Ranwel Caputto, CIQUIBIC‐CONICET, Facultad de Ciencias Químicas Universidad Nacional de Córdoba Córdoba ArgentinaDepartamento de Biotecnología Microbiana y de Plantas Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas Madrid SpainDepartamento de Biotecnología Microbiana y de Plantas Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas Madrid SpainDepartamento de Química Biológica Ranwel Caputto, CIQUIBIC‐CONICET, Facultad de Ciencias Químicas Universidad Nacional de Córdoba Córdoba ArgentinaABSTRACT In this work, we developed a plasmid‐based CRISPR‐Cas9 strategy for editing Lactococcus cremoris, which allows easy generation of plasmid‐free strains with the desired modification. We constructed versatile shuttle vectors based on the theta‐type pAMβ1 promiscuous replicon and p15A ori, expressing both the Cas9 nuclease gene (under pH‐regulated promoters derived from P170) and a single‐guide RNA for specific targeting (under a strong constitutive promoter). The vectors designed for plasmid targeting were very effective for low‐ and high‐copy‐number plasmid curing in L. cremoris, and their targeting efficiency was shown to be tunable by regulating cas9 expression. For chromosome editing, we implemented a host‐independent method that enhances double‐homologous recombination events using plasmids expressing the genes encoding λRed‐phage Redβ recombinase and Escherichia coli single‐stranded DNA binding protein (EcSSB). By coupling either the endogenous recombination machinery or the Redβ‐EcSSB‐assisted recombination system with our novel chromosome‐targeting CRISPR‐Cas9 plasmids, we efficiently generated and selected thousands of gene‐edited cells. Examination of the impact of the constructed CRISPR‐Cas9 vectors on host fitness revealed no Cas9‐associated toxicity, and, remarkably, these vectors exhibited a very high loss rate when growing the bacterial host cells in the absence of selective pressure.https://doi.org/10.1111/1751-7915.70060CRISPR‐Cas9gene‐editingLactococcus cremorisplasmid curingplasmid stability
spellingShingle Javier Nicolás Garay‐Novillo
José Ángel Ruiz‐Masó
Gloria delSolar
José Luis Barra
Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
Microbial Biotechnology
CRISPR‐Cas9
gene‐editing
Lactococcus cremoris
plasmid curing
plasmid stability
title Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
title_full Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
title_fullStr Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
title_full_unstemmed Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
title_short Easy‐Curing and pH‐Regulated CRISPR‐Cas9 Plasmids for Gene Editing and Plasmid Curing in Lactococcus cremoris
title_sort easy curing and ph regulated crispr cas9 plasmids for gene editing and plasmid curing in lactococcus cremoris
topic CRISPR‐Cas9
gene‐editing
Lactococcus cremoris
plasmid curing
plasmid stability
url https://doi.org/10.1111/1751-7915.70060
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