Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Systems biology & gene expression and signaling

BP 5.1: Hauptvortrag

Montag, 1. April 2019, 15:00–15:30, H11

Gene transfer between bacteria: from single molecules to genome dynamics — •Berenike Maier — University of Cologne

Horizontal gene transfer (HGT) plays an important role in bacterial genome evolution. Gene transfer between bacteria of different species but also between bacteria and eukaryotes has been reported. A particularly widespread mechanism of gene transfer is transformation which enables bacteria to import and inheritably integrate external DNA. The first part of the presentation will focus on the import of DNA through the cell envelope, a key step to transformation. The proteins forming the DNA uptake machine have been identified. Yet, the biophysical mechanism of the motor pulling DNA from the environment into the bacterial cell remains poorly understood. We used single molecule approaches for studying the molecular mechanism of DNA uptake. Our results are in remarkable agreement with a translocation ratchet model, whereby a periplasmic chaperone rectifies DNA diffusion through the membrane by reversible binding. In the second part, the I will address the question how gene transfer between different bacterial subspecies affects genome dynamics and bacterial fitness. Using laboratory evolution, we show that despite considerable sequence divergence, large portions of the genome are rapidly transferred.