Skip to Main content Skip to Navigation
New interface
Theses

Évolution des génomes de bactériophages

Abstract : Bacteriophage genomes have a remarkable ability to evolve. The aim of my thesis was to study the role of bacteriophage recombinases in this evolution. Our hypothesis was that such recombinases differ from the bacterial RecA recombinase by a relaxed fidelity during homology search, which may partly explain the high plasticity of bacteriophage genomes. We first used a bioinformatics approach based on remote homology search to predict a maximum of recombinase genes in completely sequenced genomes, and confirmed the recombination activity of some of them by a single-strand DNA annealing assay between identical sequences in vivo. This allowed us to conclude that there were three superfamilies of bacteriophage recombinases, Rad52-like, Rad51/RecA-like and Gp2.5-like, which were present in 42% of the 465 genomes analyzed. In a second step, we compared six of these recombinases to RecA and showed that all were able to anneal single-stranded DNA in vivo, in contrast to RecA. For two of them, Redβ of Lambda (Rad52-like) and Sak4 of HK620 (Rad51/RecAlike), we also observed that they were able to anneal non identical (13% of divergence) single-stranded DNA, with a reduced efficiency. We conclude that the single-stranded DNA annealing is a property common to recombinases of bacteriophages, which is absent in RecA, and seems to tolerate diverged sequences. This supports the hypothesis of a different and more relaxed recombination in bacteriophages.
Document type :
Theses
Complete list of metadata

Cited literature [143 references]  Display  Hide  Download

https://theses.hal.science/tel-00923139
Contributor : ABES STAR :  Contact
Submitted on : Thursday, January 2, 2014 - 1:21:43 AM
Last modification on : Friday, August 5, 2022 - 2:38:10 PM
Long-term archiving on: : Saturday, April 8, 2017 - 8:41:16 AM

File

VD2_AMARIR-BOUHRAM_JIHANE_0903...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00923139, version 1

Citation

Jihane Amarir-Bouhram. Évolution des génomes de bactériophages. Sciences agricoles. Université Paris Sud - Paris XI, 2012. Français. ⟨NNT : 2012PA112036⟩. ⟨tel-00923139⟩

Share

Metrics

Record views

292

Files downloads

438