Biology subjects

Uebe, R.

Publications and source records attributed to Uebe, R..

3 recordsLinked to original sources

bioRxiv2025

Engineering NIR-Sighted Bacteria

Spatially and temporally orchestrated gene expression underpins organismal development, physiology, and adaptation. In bacteria, two-component systems (TCS) translate environmental cues into inducible expression outputs. Inducible expression also serves as a versatile instrument in both basic and applied science. Here, we harness the photosensors of rhizobial bathy-phytochromes to construct synthetic TCSs for stringent activation of gene expression by near-infrared (NIR) light in laboratory and probiotic Escherichia coli strains, and in Agrobacterium tumefaciens. Orthogonal TCSs afford the multiplexed expression control of several genes by NIR and visible light. Notwithstanding substantial photochemical activation of bathy-phytochromes by visible radiation, the NIR-light-responsive systems hardly responded to red light. Evidently, light signals can be processed by TCSs into highly nonlinear responses at the physiological relevant level of gene expression. These fundamental aspects likely extend to naturally occurring TCSs. Depending on their photosensor traits and environmental conditions, bathy-phytochromes may thus either be NIR-specific or function as colorblind receptors of light vs. darkness.

biochemistry↗

bioRxiv2023

Homologs of the plastidal preprotein translocase Tic20 mediate organelle assembly in bacteria

Organelle-specific protein translocation systems are essential for organelle biogenesis and maintenance in eukaryotes but thought to be absent from prokaryotic organelles. Here, we identified that MamF-like proteins involved in the formation of bacterial magnetosome organelles share an ancient origin with Tic20 protein translocases found in chloroplasts. Deletion of mamF-like genes in the alphaproteobacterium Magnetospirillum gryphiswaldense results in severe defects in organelle positioning, biomineralization, and magnetic navigation. Consistent with translocase-like functions, these defects are caused by the loss of magnetosome targeting of a subset of organellar proteins containing C-terminal glycine-rich integral membrane domains. Our findings suggest that organelle-specific protein translocation systems may indeed play a role in bacterial organelle formation.

microbiology↗

bioRxiv2022

Hidden Talents: Silent Gene Clusters Encoding Magnetic Organelle Biosynthesis in a Non-Magnetotactic Phototrophic Bacterium

Horizontal gene transfer is a powerful source of innovations in prokaryotes that can affect almost any cellular system, including microbial organelles. However, typically rapid loss of non-functional gene acquisitions obscures the mechanisms determining the fate of horizontally transferable genes. Here, we report the first discovery of a horizontally inherited gene cluster encoding biosynthesis of magnetosomes, the organelles used by magnetotactic bacteria for navigation, in a non-magnetotactic phototrophic bacterium Rhodovastum atsumiense. We show that these clusters were inactivated through transcriptional silencing and antisense RNA regulation, but retain functionality, as several genes were able to complement the orthologous deletions in a remotely related magnetotactic bacterium. The laboratory transfer of foreign magnetosome genes to R. atsumiense was found to endow the strain with magnetosome biosynthesis, but strong negative selection led to rapid loss of this trait upon subcultivation. Our results provide insight into the horizontal dissemination of gene clusters encoding complex prokaryotic organelles and illuminate the potential mechanisms of their genomic preservation in a dormant state.

microbiology↗