Control of a gene transfer agent cluster in Caulobacter crescentus by transcriptional activation and anti-termination

• Published in: Nature communications 2024-06, Vol.15 (1), p.4749-18, Article 4749
• Main Authors: Tran, Ngat T., Le, Tung B. K.
• Format: Article
• Language: English
• Subjects: 38; 38/15; 38/88; 49; 631/326/1320; 631/326/325/2482; 64; 82/1; 82/29; 82/83; Alpha rays; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriophages - genetics; Caulobacter crescentus; Caulobacter crescentus - genetics; Caulobacter crescentus - metabolism; Cell cycle; Clusters; DNA-directed RNA polymerase; Gene expression; Gene Expression Regulation, Bacterial; Gene regulation; Gene transfer; Humanities and Social Sciences; Integration host factor; multidisciplinary; Multigene Family; Phages; RNA polymerase; Science; Science (multidisciplinary); Synthesis; Transcription activation; Transcription termination; Transcription Termination, Genetic; Transcription, Genetic; Transcriptional Activation
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49114-2

Gene Transfer Agents (GTAs) are phage-like particles that cannot self-multiply and be infectious. Caulobacter crescentus , a bacterium best known as a model organism to study bacterial cell biology and cell cycle regulation, has recently been demonstrated to produce bona fide GTA particles (CcGTA). Since C. crescentus ultimately die to release GTA particles, the production of GTA particles must be tightly regulated and integrated with the host physiology to prevent a collapse in cell population. Two direct activators of the CcGTA biosynthetic gene cluster, GafY and GafZ, have been identified, however, it is unknown how GafYZ controls transcription or how they coordinate gene expression of the CcGTA gene cluster with other accessory genes elsewhere on the genome for complete CcGTA production. Here, we show that the CcGTA gene cluster is transcriptionally co-activated by GafY, integration host factor (IHF), and by GafZ-mediated transcription anti-termination. We present evidence that GafZ is a transcription anti-terminator that likely forms an anti-termination complex with RNA polymerase, NusA, NusG, and NusE to bypass transcription terminators within the 14 kb CcGTA cluster. Overall, we reveal a two-tier regulation that coordinates the synthesis of GTA particles in C. crescentus . This study reveals that in the alpha-proteobacterium, Caulobacter crescent , a two-tier regulation by transcriptional activation and anti-termination coordinates the synthesis of phage-like Gene Transfer Agents (GTA) particles.