Native CRISPR-Cas-based programmable multiplex gene repression in Klebsiella variicola

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Klebsiella variicola is an opportunistic pathogen with biotechnological potential.
• Understanding its pathogenesis and beneficial activities is hindered by a lack of genetic tools.
• A native type I-E CRISPR-Cas system was identified in K. variicola strain KV-1.

Purpose of the Study:

• To characterize the native type I-E CRISPR-Cas system in K. variicola KV-1.
• To repurpose the system for targeted gene repression.
• To develop a tool for programmable multiplex gene repression in K. variicola.

Main Methods:

• Identification and characterization of a type I-E CRISPR-Cas system in K. variicola KV-1.
• Design and introduction of a targeting plasmid with a mini-CRISPR array.
• Demonstration of specific gene expression inhibition and multiplex gene repression.

Main Results:

• The native type I-E CRISPR-Cas system in KV-1 retains crRNA-guided Cascade DNA binding activity.
• Repurposing the system via a targeting plasmid achieved efficient and specific target gene repression.
• Multiplex gene repression was successfully demonstrated using a single targeting plasmid encoding multiple crRNAs.

Conclusions:

• A novel CRISPR-Cas-based tool for programmable multiplex gene repression in K. variicola was developed.
• This tool facilitates the study of K. variicola pathogenesis.
• The tool enables metabolic engineering for the production of valuable bioproducts.