SspA is a transcriptional regulator of CRISPR adaptation in E. coli

• Published in: Nucleic acids research 2024-12
• Main Authors: Lopez, Santiago C, Lee, Yumie, Zhang, Karen, Shipman, Seth L
• Format: Article
• Language: English
• ISSN: 0305-1048; 1362-4962; 1362-4962
• DOI: 10.1093/nar/gkae1244

The CRISPR integrases Cas1-Cas2 create immunological memories of viral infection by storing phage-derived DNA in CRISPR arrays, a process known as CRISPR adaptation. A number of host factors have been shown to influence adaptation, but the full pathway from infection to a fully integrated, phage-derived sequences in the array remains incomplete. Here, we deploy a new CRISPRi-based screen to identify putative host factors that participate in CRISPR adaptation in the Escherichia coli Type I-E system. Our screen and subsequent mechanistic characterization reveal that SspA, through its role as a global transcriptional regulator of cellular stress, is required for functional CRISPR adaptation. One target of SspA is H-NS, a known repressor of CRISPR interference proteins, but we find that the role of SspA on adaptation is not H-NS-dependent. We propose a new model of CRISPR-Cas defense that includes independent cellular control of adaptation and interference by SspA.