Molecular Microbiology and Structural Biochemistry (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007, Lyon, France.
Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
Nat Commun. 2023 Jan 18;14(1):294. doi: 10.1038/s41467-023-35978-3.
Conjugation is a contact-dependent mechanism for the transfer of plasmid DNA between bacterial cells, which contributes to the dissemination of antibiotic resistance. Here, we use live-cell microscopy to visualise the intracellular dynamics of conjugative transfer of F-plasmid in E. coli, in real time. We show that the transfer of plasmid in single-stranded form (ssDNA) and its subsequent conversion into double-stranded DNA (dsDNA) are fast and efficient processes that occur with specific timing and subcellular localisation. Notably, the ssDNA-to-dsDNA conversion determines the timing of plasmid-encoded protein production. The leading region that first enters the recipient cell carries single-stranded promoters that allow the early and transient synthesis of leading proteins immediately upon entry of the ssDNA plasmid. The subsequent conversion into dsDNA turns off leading gene expression, and activates the expression of other plasmid genes under the control of conventional double-stranded promoters. This molecular strategy allows for the timely production of factors sequentially involved in establishing, maintaining and disseminating the plasmid.
conjugation 是细菌细胞间质粒 DNA 转移的一种接触依赖机制，有助于抗生素耐药性的传播。在这里，我们使用活细胞显微镜实时可视化大肠杆菌中 F 质粒的接合转移的细胞内动力学。我们表明，单链形式（ssDNA）的质粒转移及其随后转化为双链 DNA（dsDNA）是快速而高效的过程，具有特定的时间和亚细胞定位。值得注意的是，ssDNA 到 dsDNA 的转化决定了质粒编码蛋白产生的时间。首先进入受体细胞的先导区携带单链启动子，允许 ssDNA 质粒进入后立即进行先导蛋白的早期和瞬时合成。随后转化为 dsDNA 会关闭先导基因的表达，并激活在常规双链启动子控制下的其他质粒基因的表达。这种分子策略允许依次参与建立、维持和传播质粒的因素及时产生。
