The promise of CRISPR-associated transposons for bacterial functional genomics.

CRISPR-associated transposons (CASTs) are naturally occurring amalgamations of CRISPR-Cas machinery and Tn7-like transposons that direct site-specific integration of transposon DNA via programmable guide RNAs. Although the mechanisms of CAST-based transposition have been well studied at the molecular and structural level, CASTs have yet to be broadly applied to bacterial genome engineering and systematic gene phenotyping (i.e.

BR-bodies promote fitness during host colonization.

Biomolecular condensates, such as the nucleoli or P-bodies, are non-membrane-bound assemblies of proteins and nucleic acids that facilitate specific cellular processes. Like eukaryotic P-bodies, the recently discovered bacterial ribonucleoprotein bodies (BR-bodies) organize the mRNA decay machinery, yet the similarities in molecular and cellular functions across species have been poorly explored. Here, we examine the functions of BR-bodies in the nitrogen-fixing endosymbiont , which colonizes the roots of compatible legume plants.

A Targeted Genome-scale Overexpression Platform for Proteobacteria.

Targeted, genome-scale gene perturbation screens using Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) and activation (CRISPRa) have revolutionized eukaryotic genetics, advancing medical, industrial, and basic research. Although CRISPRi knockdowns have been broadly applied in bacteria, options for genome-scale overexpression face key limitations. Here, we develop a facile approach for genome-scale gene overexpression in bacteria we call, "CRISPRtOE" (CRISPR transposition and OverExpression).

A protease and a lipoprotein jointly modulate the conserved ExoR-ExoS-ChvI signaling pathway critical in Sinorhizobium meliloti for symbiosis with legume hosts.

Sinorhizobium meliloti is a model alpha-proteobacterium for investigating microbe-host interactions, in particular nitrogen-fixing rhizobium-legume symbioses. Successful infection requires complex coordination between compatible host and endosymbiont, including bacterial production of succinoglycan, also known as exopolysaccharide-I (EPS-I). In S.