Publications by authors named "Annick Berne-Dedieu"

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.

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Drug-efflux by pump proteins is one of the major mechanisms of antibiotic resistance in bacteria. Here, we use quantitative fluorescence microscopy to investigate the real-time dynamics of drug accumulation and efflux in live E. coli cells.

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Article Synopsis
  • Plant and animal cells have developed different strategies for their growth, but how their cell mechanics compare has not been clear due to separate experimental setups.
  • This study used the same equipment to examine the rheology (flow behavior) of both types of cells and found that wall-less plant cells behave similarly to animal cells in terms of their mechanical properties.
  • The researchers discovered that while microtubules influenced the plant cells' rheology, the animal cells relied more on their actin networks, suggesting that both have evolved distinct molecular strategies to achieve similar mechanical characteristics.
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Organ morphogenesis largely relies on cell division and elongation, which need to be both coordinated between cells and orchestrated with cytoskeleton dynamics. However, components that bridge the biological signals and the effectors that define cell shape remain poorly described. We have addressed this issue through the functional characterisation of QUIRKY (QKY), previously isolated as being involved in the STRUBBELIG (SUB) genetic pathway that controls cell-cell communication and organ morphogenesis in Arabidopsis.

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The retromer complex localizes to endosomal membranes and is involved in protein trafficking. In mammals, it is composed of a dimer of sorting nexins and of the core retromer consisting of vacuolar protein sorting (VPS)26, VPS29, and VPS35. Although homologs of these proteins have been identified in plants, how the plant retromer functions remains elusive.

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Article Synopsis
  • Auxin response factors (ARF) are essential for plant development as they respond to the hormone auxin by regulating gene expression, thanks to their unique four-domain structure.
  • A study on 224 ARF-related protein sequences across various land plants revealed three subfamilies of ARFs dating back to the earliest land plants, with gene duplication events playing a key role in their expansion.
  • The research also identified genetic changes like domain loss and alternative splicing that lead to structural diversity in ARF proteins, influencing their functional roles in plant development, as seen with the ARF4 isoform in Arabidopsis thaliana.
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Here we analyze the structural evolution of the paralogous transcription factors ETTIN (ETT/ARF3) and AUXIN RESPONSE FACTOR 4 (ARF4), which control the development of floral organs and leaves in the model angiosperm Arabidopsis. ETT is truncated at its C terminus, and consequently lacks two regulatory domains present in most other ARFs, including ARF4. Our analysis indicates ETT and ARF4 to have been generated by the duplication of a non-truncated ARF gene prior to the radiation of the extant angiosperms.

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Background And Aims: CRABS CLAW (CRC) encodes a transcription factor of the YABBY family that plays important roles in carpel and nectary development in Arabidopsis thaliana. Combined evolutionary and developmental studies suggest an ancestor of the CRC gene to have controlled carpel development in the last common ancestor of the angiosperms. Roles for CRC orthologues in leaf development and carpel specification in rice, and in nectary development in core eudicots, have accordingly been interpreted as derived.

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