CRISPR–Cas regulates expression of embedded anti-phage defence systems

TL;DR - CRISPR–Cas systems regulate embedded innate anti-phage defences through CRISPR RNA-like guides, balancing antiviral protection against bacterial fitness costs. When those defences are compromised, CRISPR–Cas hyperactivates them to create a layered “immunity guard” network.

• CRISPR–Cas transcriptionally tunes multiple innate defence systems.
• CRISPR RNA-like guides mediate this regulatory function.
• Regulation balances phage resistance with host fitness.
• Compromised defences trigger compensatory hyperactivation.