In vivo CRISPRi screens reveal Escherichia coli functional adaptations in the mouse gut.

In vivo CRISPRi screens identified that E. coli's genetic requirements for gut colonization vary among strains and are influenced by diet and host inflammation.

• Why it matters: Understanding how E. coli adapts genetically to the gut environment is crucial for insights into microbial colonization and pathogenicity, addressing gaps in functional genomics within host systems.
• What they did: Researchers developed an in vivo CRISPR interference platform to assess gene fitness in E. coli strains within mice with a minimal microbial community, revealing strain-specific and environment-dependent genetic adaptations.
• The result: The study provides a detailed genetic atlas of E. coli's gut adaptation, showing diet and inflammation shape essential genes and highlighting the role of mobile genetic elements like Gally prophage in colonization.