Regulation of CRISPR‐Cas Expression and Function

Smith, Lisa F.; Campa, Aroa Rey; Fineran, Peter C.

doi:10.1002/9781683673798.ch10

Cited by 2 publications

(3 citation statements)

References 142 publications

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“…Therefore, in the absence of invaders, it is vital for bacteria to limit CRISPR-Cas activity and the potential costs. Conversely, when exposed to invaders, an elevated immune response is desirable ( 19 , 20 ).…”

Section: Introductionmentioning

confidence: 99%

“…While there have been considerable advances in deciphering adaptation, processing and interference, regulation of CRISPR-Cas expression is less well understood ( 19 , 20 ). One conserved form of CRISPR-Cas regulation is through quorum sensing (QS), a widespread form of cell-cell communication in which accumulation of extracellular chemical signals can alter population gene expression ( 21 ).…”

Section: Introductionmentioning

confidence: 99%

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CRISPR-Cas immunity is repressed by the LysR-type transcriptional regulator PigU

Smith,

Hampton,

Yevstigneyeva

et al. 2023

Nucleic Acids Research

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Bacteria protect themselves from infection by bacteriophages (phages) using different defence systems, such as CRISPR-Cas. Although CRISPR-Cas provides phage resistance, fitness costs are incurred, such as through autoimmunity. CRISPR-Cas regulation can optimise defence and minimise these costs. We recently developed a genome-wide functional genomics approach (SorTn-seq) for high-throughput discovery of regulators of bacterial gene expression. Here, we applied SorTn-seq to identify loci influencing expression of the two type III-A Serratia CRISPR arrays. Multiple genes affected CRISPR expression, including those involved in outer membrane and lipopolysaccharide synthesis. By comparing loci affecting type III CRISPR arrays and cas operon expression, we identified PigU (LrhA) as a repressor that co-ordinately controls both arrays and cas genes. By repressing type III-A CRISPR-Cas expression, PigU shuts off CRISPR-Cas interference against plasmids and phages. PigU also represses interference and CRISPR adaptation by the type I-F system, which is also present in Serratia. RNA sequencing demonstrated that PigU is a global regulator that controls secondary metabolite production and motility, in addition to CRISPR-Cas immunity. Increased PigU also resulted in elevated expression of three Serratia prophages, indicating their likely induction upon sensing PigU-induced cellular changes. In summary, PigU is a major regulator of CRISPR-Cas immunity in Serratia.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CRISPR-Cas immunity is repressed by the LysR-type transcriptional regulator PigU

Smith,

Hampton,

Yevstigneyeva

et al. 2023

Nucleic Acids Research

View full text Add to dashboard Cite

show abstract

“…The Gram-negative soil myxobacterium Myxococcus xanthus is a model organism to study bacterial multicellularity, motility, social behavior, light response, predation, and biosynthesis of lipids, steroids, and secondary metabolites ( 1 – 6 ). Its large genome contains three CRISPR-Cas systems ( 7 , 8 ), and the regulation of two of these has been examined ( 7 , 9 , 10 ). However, their role in phage defense remains unexplored.…”

Section: Announcementmentioning

confidence: 99%