Unravelling the DNA sequences carried by Streptomyces coelicolor membrane vesicles

Membrane vesicles (MVs) are spherical particles with nanoscale dimensions and characterized by the presence of diverse cargos, such as nucleic acids, proteins, lipids, and cellular metabolites. Many examples of (micro)organisms producing MVs are reported in literature. Among them, bacterial MVs are of particular interest because they are now considered as the fourth mechanism of horizontal gene transfer. Streptomyces bacteria are well-known for their ecological roles and ability to synthesize bioactive compounds, with Streptomyces coelicolor being the model organism. It was previously demonstrated that it can produce distinct populations of MVs characterized by different protein and metabolite cargos. In this work we demonstrated for the first time that MVs of S. coelicolor carry both DNA and RNA and that their DNA content represents the entire chromosome of the bacterium. These findings suggest that MV DNA could have a role in the evolution of Streptomyces genomes and that MVs could be exploited in new strain engineering strategies.

Automated summary

Membrane vesicles (MVs) are nanoscale spherical particles that carry diverse cargos. Bacterial MVs, including those from Streptomyces coelicolor, have been identified as a fourth mechanism of horizontal gene transfer. This study demonstrates for the first time that MVs from S. coelicolor carry both DNA and RNA, with the DNA content representing the entire chromosome of the bacterium. These findings highlight the potential significance of MVs in the evolution of Streptomyces genomes and strain engineering strategies.