CMDNAUP · Composition and Mechanism of the DNA-uptake Pilus of Vibrio cholerae
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2016-09-01 → 2018-08-31
- EU contribution
- €175,420
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
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Results in brief
Composition and Mechanism of the DNA-uptake Pilus of Vibrio cholerae
Horizontal gene transfer (HGT), the ability to acquire novel genes from other organisms, can facilitate rapid bacterial evolution including the spread of genes encoding antibiotic resistance and virulence factors. One widely used form of HGT is natural competence for transformation, which allows bacteria to take up DNA from the environment and maintain it in a heritable state. In the Gram-negative bacterium Vibrio cholerae, which is an important human pathogen that causes the pandemic disease Cholera, natural competence is activated during growth on chitinous surfaces, which are ubiquitous in the aquatic environment. To transport DNA into the cell, competent bacteria use type IV pili, a widespread and versatile class of cell surface polymers. Recent work from our laboratory established that V. cholerae produces a bona fide DNA-uptake pilus composed of the major pilin subunit PilA, and that DNA-uptake requires the combined action of this pilus and a periplasmic DNA-binding protein called ComEA. These results were consistent with the long-standing model in which the pilus retracts to bring DNA into the periplasm. However, although well supported by genetic evidence this process had never been visualised in action. Therefore the main objective of this action was to visualise the DNA-uptake pilus in live cells and investigate its dynamics.
Data: CORDIS, © European Union
Project objective
Horizontal gene transfer (HGT) allows rapid bacterial evolution including the spread of genes encoding antibiotic resistance and virulence factors. The Gram-negative bacterium Vibrio cholerae is an important human pathogen that causes the pandemic disease Cholera. In its natural aquatic environment growth on the chitinous exoskeletons of zooplankton initiates the development of ‘Natural Competence’, a widespread and key form of HGT that allows bacteria to take up free DNA from the environment. DNA uptake involves a sophisticated nanomachine known as a Type IV Pilus (TFP), which forms polymeric extensions from the cell surface, are ubiquitous throughout bacteria and play a wide range of other roles such as surface motility and attachment. Notably, this machinery is conserved in other naturally competent bacteria including in several important human pathogens, implying a common mode of action. Work on this machinery has mainly been done in Gram-positive models like Bacillus subtilis but had failed to visualise an uptake pilus. Recently, the Blokesch lab visualised a DNA uptake pilus extending from the outer membrane of V. cholerae and determined the minimal known components needed for its assembly. However, we still know almost nothing about how this machinery actually works to bring DNA into the cell. To answer this important question and elucidate the underlying molecular mechanisms we will follow two main objectives. 1. We will determine the composition of purified DNA-uptake pili and investigate the functions of the identified proteins. 2. We will combine innovative genetic and cell-biological approaches to investigate the mechanism of DNA uptake. The Blokesch lab at EPFL has pioneered genetic and cell biological methods for studying competence in V. cholerae and has state-of-the-art equipment and infrastructures that offer the prospective fellow the maximum chance of success and the best-possible training through the research.
Original text from CORDIS.
Participants
- ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE · LausanneCoordinatorSwitzerland
Links
Data: CORDIS, © European Union