Functional diversification of Paramecium Ku80 paralogs safeguards genome integrity during precise programmed DNA elimination - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue PLoS Genetics Année : 2020

Functional diversification of Paramecium Ku80 paralogs safeguards genome integrity during precise programmed DNA elimination

Résumé

Gene duplication and diversification drive the emergence of novel functions during evolution. Because of whole genome duplications, ciliates from the Paramecium aurelia group constitute a remarkable system to study the evolutionary fate of duplicated genes. Paramecium species harbor two types of nuclei: a germline micronucleus (MIC) and a somatic macronucleus (MAC) that forms from the MIC at each sexual cycle. During MAC development, ~45,000 germline Internal Eliminated Sequences (IES) are excised precisely from the genome through a 'cut-and-close' mechanism. Here, we have studied the P. tetraurelia paralogs of KU80, which encode a key DNA double-strand break repair factor involved in non-homologous end joining. The three KU80 genes have different transcription patterns, KU80a and KU80b being constitutively expressed, while KU80c is specifically induced during MAC development. Immunofluorescence microscopy and high-throughput DNA sequencing revealed that Ku80c stably anchors the PiggyMac (Pgm) endonuclease in the developing MAC and is essential for IES excision genome-wide, providing a molecular explanation for the previously reported Ku-dependent licensing of DNA cleavage at IES ends. Expressing Ku80a under KU80c transcription signals failed to complement a depletion of endogenous Ku80c, indicating that the two paralogous proteins have distinct properties. Domain-swap experiments identified the α/β domain of Ku80c as the major determinant for its specialized function, while its C-terminal part is required for excision of only a small subset of IESs located in IES-dense regions. We conclude that Ku80c has acquired the ability to license Pgm-dependent DNA cleavage, securing precise DNA elimination during programmed rearrangements. The present study thus provides novel evidence for functional diversification of genes issued from a whole-genome duplication.
Fichier principal
Vignette du fichier
2020Abello_PLoSGenet_functional specialization of Ku80c.pdf (2.7 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-02547876 , version 1 (09-11-2020)

Identifiants

Citer

Arthur Abello, Vinciane Régnier, Olivier Arnaiz, Romain Le Bars, Mireille Bétermier, et al.. Functional diversification of Paramecium Ku80 paralogs safeguards genome integrity during precise programmed DNA elimination. PLoS Genetics, 2020, 16 (4), pp.e1008723. ⟨10.1371/journal.pgen.1008723⟩. ⟨hal-02547876⟩
28 Consultations
49 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More