%0 Journal Article
%A Aguilera, Paula
%A Dubarry, Marion
%A Hardy, Julien
%A Lisby, Michael
%A Simon, Marie-Noëlle
%A Géli, Vincent
%T Telomeric C-circles localize at nuclear pore complexes in Saccharomyces cerevisiae.
%D 2022
%U http://hdl.handle.net/10668/21694
%X As in human cells, yeast telomeres can be maintained in cells lacking telomerase activity by recombination-based mechanisms known as ALT (Alternative Lengthening of Telomeres). A hallmark of ALT human cancer cells are extrachromosomal telomeric DNA elements called C-circles, whose origin and function have remained unclear. Here, we show that extrachromosomal telomeric C-circles in yeast can be detected shortly after senescence crisis and concomitantly with the production of survivors arising from "type II" recombination events. We uncover that C-circles bind to the nuclear pore complex (NPC) and to the SAGA-TREX2 complex, similar to other non-centromeric episomal DNA. Disrupting the integrity of the SAGA/TREX2 complex affects both C-circle binding to NPCs and type II telomere recombination, suggesting that NPC tethering of C-circles facilitates formation and/or propagation of the long telomere repeats characteristic of type II survivors. Furthermore, we find that disruption of the nuclear diffusion barrier impairs type II recombination. These results support a model in which concentration of C-circles at NPCs benefits type II telomere recombination, highlighting the importance of spatial coordination in ALT-type mechanisms of telomere maintenance.
%K C-circles
%K alternative lengthening of telomeres
%K recombination
%K senescence
%K telomeres
%~