Gene transfer agents (GTAs) are thought to be ancient bacteriophages that have been co-
opted into serving their host and can now transfer any gene between bacteria. Production of
GTAs is controlled by several global regulators through unclear mechanisms. In
Rhodobacter capsulatus, gene rcc01865 encodes a putative regulatory protein that is
essential for GTA production. Here, I show that rcc01865 (hereafter gafA) encodes a
transcriptional regulator that binds to the GTA promoter to initiate production of structural and …