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16 avril 2021: 1 événement

  • Département Biologie des Génomes

    Vendredi 16 avril 11:00-12:00 - Jose Antonio ESCUDERO - Universidad Complutense de Madrid

    Evolutionary History of Integrons

    Résumé : Integrons are genetic platforms that act as bacterial memories of adaptive functions, accelerating evolution in changing environments. They were discovered on conjugative plasmids for their role in the early rise of multidrug resistance, but they are naturally found in the chromosomes of many bacterial species, where they have driven their evolution for aeons. Integrons recruit, stockpile and modulate the expression of new genes encoded in small mobile structures named cassettes. The streamlined functionality of integrons is based on the DNA transactions performed by the integrase –that integrates, excises and reshuffles cassettes-, and the peculiarities of the recombination sites.
    Yet integrons have an interesting evolutionary origin themselves. In this seminar, we will see how they have evolved from the tyrosine recombinase family of proteins through a process of evolutionary innovation. I will explain how the activity of these ancestors has been extensively modified to deliver the modern activity of today’s integrases through the co-evolution of the integrase and the attC recombination site. We will discuss the main biological implications of this evolutionary process in an attempt to establish the selective forces driving it, and the meaning of the coexistence of ancestral and modern activities. We will end by deciphering the structural basis of both activities and their trade-offs through an attempt to rewind the tape of evolutionary innovation.
    Invited by Virginia Lioy Lioy <virginia.lioy i2bc.paris-saclay.fr>

    Lieu : visio

    En savoir plus : Département Biologie des Génomes