Guaranteeing a captive audience: coordinated regulation of gene transfer agent (GTA) production and recipient capability by cellular regulators

•Gene transfer agents (GTAs) are phage-like particles mediating gene transfer.•The Rhodobacter capsulatus GTA (RcGTA) is produced by a subpopulation.•RcGTA-like particles are produced by several Alphaproteobacteria.•Natural transformation-like genes are required to receive donated DNA.•The response regulator CtrA controls both RcGTA production and recipient capability.

Gene transfer agents (GTAs) are bacteriophage-like particles produced by many prokaryotes. Several members of the Alphaproteobacteria produce a class of genetically-related GTAs that is best studied in Rhodobacter capsulatus. DNA transfer by the R. capsulatus GTA (RcGTA) combines aspects of both transduction and natural transformation, as recipient cells require a natural transformation-like system to incorporate donated DNA. The genes involved in RcGTA production and recipient capability are located at multiple loci in the bacterial genome; however, a conserved phosphorelay containing the response regulator CtrA and a quorum sensing system regulate both RcGTA production and recipient capability. This review highlights recent discoveries in RcGTA biology, and focuses on the co-regulation of genes involved in RcGTA production and recipient capability.

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