Cell-envelope conduits enable transfer of megabase-sized double-stranded DNA between cells of the nosocomial pathogen Acinetobacter baumannii
- 1Goethe University Frankfurt
Abstract
Horizontal gene transfer in Acinetobacter baumannii has been attributed to conjugative pili, transduction, and natural transformation. Here, we describe a previously unrecognized type of chromosomal DNA exchange mediated by cell-envelope conduits that establish direct cytoplasmic continuity between neighboring A. baumannii cells. Cryo-electron tomography reveals that these conduits, which were found in multiple clinical isolates, comprise an outer membrane, a peptidoglycan layer, and an inner membrane. The ~65 nm-thick conduits contain two ~2 nm-thick filaments, which super-resolution microscopy identifies as DNA. Interstrain horizontal gene transfer assays coupled with whole-genome sequencing demonstrate the transfer and homologous recombination of chromosomal segments up to 1.1 Mbp, corresponding to as much as 27% of the A. baumannii genome. Together, these findings provide direct structural and functional evidence for a conduit-mediated large-scale chromosomal DNA exchange, thus expanding the known repertoire of horizontal gene transfer strategies that may contribute to the remarkable genomic plasticity of A. baumannii.
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BibTeX
@misc{manger2026cellenvelope,
title = {{Cell-envelope conduits enable transfer of megabase-sized double-stranded DNA between cells of the nosocomial pathogen Acinetobacter baumannii}},
author = {S. Manger and C. Boernsen and S. G. Torres and P. Roth and J. Sommer and A. Balakrishnan and F. Langschied and C. Thiel and I. Haenelt and M. Heilemann and S. Goettig and I. Ebersberger and K. M. Pos and A. Frangakis},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.02.748809},
url = {https://www.biorxiv.org/content/10.64898/2026.09.02.748809v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Cell-envelope conduits enable transfer of megabase-sized double-stranded DNA between cells of the nosocomial pathogen Acinetobacter baumannii
AU - S. Manger
AU - C. Boernsen
AU - S. G. Torres
AU - P. Roth
AU - J. Sommer
AU - A. Balakrishnan
AU - F. Langschied
AU - C. Thiel
AU - I. Haenelt
AU - M. Heilemann
AU - S. Goettig
AU - I. Ebersberger
AU - K. M. Pos
AU - A. Frangakis
PY - 2026
DA - 2026/09/02
PB - bioRxiv
DO - 10.64898/2026.09.02.748809
UR - https://www.biorxiv.org/content/10.64898/2026.09.02.748809v1
AB - Horizontal gene transfer in Acinetobacter baumannii has been attributed to conjugative pili, transduction, and natural transformation. Here, we describe a previously unrecognized type of chromosomal DNA exchange mediated by cell-envelope conduits that establish direct cytoplasmic continuity between neighboring A. baumannii cells. Cryo-electron tomography reveals that these conduits, which were found in multiple clinical isolates, comprise an outer membrane, a peptidoglycan layer, and an inner membrane. The ~65 nm-thick conduits contain two ~2 nm-thick filaments, which super-resolution microscopy identifies as DNA. Interstrain horizontal gene transfer assays coupled with whole-genome sequencing demonstrate the transfer and homologous recombination of chromosomal segments up to 1.1 Mbp, corresponding to as much as 27% of the A. baumannii genome. Together, these findings provide direct structural and functional evidence for a conduit-mediated large-scale chromosomal DNA exchange, thus expanding the known repertoire of horizontal gene transfer strategies that may contribute to the remarkable genomic plasticity of A. baumannii.
ER -