| Autor: |
Bischerour, Julien, Arnaiz, Olivier, Zangarelli, Coralie, Régnier, Vinciane, Iehl, Florence, Ropars, Virginie, Charbonnier, Jean-Baptiste, Bétermier, Mireille |
| Zdroj: |
Cell Reports; April 2024, Vol. 43 Issue: 4 |
| Abstrakt: |
In the ciliate Paramecium, precise excision of numerous internal eliminated sequences (IESs) from the somatic genome is essential at each sexual cycle. DNA double-strands breaks (DSBs) introduced by the PiggyMac endonuclease are repaired in a highly concerted manner by the non-homologous end joining (NHEJ) pathway, illustrated by complete inhibition of DNA cleavage when Ku70/80 proteins are missing. We show that expression of a DNA-binding-deficient Ku70 mutant (Ku70-6E) permits DNA cleavage but leads to the accumulation of unrepaired DSBs. We uncoupled DNA cleavage and repair by co-expressing wild-type and mutant Ku70. High-throughput sequencing of the developing macronucleus genome in these conditions identifies the presence of extremities healed by de novotelomere addition and numerous translocations between IES-flanking sequences. Coupling the two steps of IES excision ensures that both extremities are held together throughout the process, suggesting that DSB repair proteins are essential for assembly of a synaptic precleavage complex. |
| Databáze: |
Supplemental Index |
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