Repair of UV-induced DNA lesions in natural Saccharomyces cerevisiae telomeres is moderated by Sir2 and Sir3, and inhibited by yKu-Sir4 interaction.
Ultraviolet light (UV) causes DNA damage that is removed by nucleotide excision repair (NER). UV-induced DNA lesions must be recognized and repaired in nucleosomal DNA, higher order structures of chromatin and within different nuclear sub-compartments. Telomeric DNA is made of short tandem repeats located at the ends of chromosomes and their maintenance is critical to prevent genome instability. In Saccharomyces cerevisiae the chromatin structure of natural telomeres is distinctive and contingent to telomeric DNA sequences. Namely, nucleosomes and Sir proteins form the heterochromatin like structure of X-type telomeres, whereas a more open conformation is present at Y'-type telomeres. It is proposed that there are no nucleosomes on the most distal telomeric repeat DNA, which is bound by a complex of proteins and folded into higher order structure. How these structures affect NER is poorly understood. Our data indicate that the X-type, but not the Y'-type, sub-telomeric chromatin modulates NER, a consequence of Sir protein-dependent nucleosome stability. The telomere terminal complex also prevents NER, however, this effect is largely dependent on the yKu-Sir4 interaction, but Sir2 and Sir3 independent.
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Laetitia
L
Guintini
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Maxime
M
Tremblay
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Martin
M
Toussaint
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Annie
A
D'Amours
Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, CSIC, Avda Américo Vespucio s/n, Sevilla 41092, Spain.
Ralf E
RE
Wellinger
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Raymund J
RJ
Wellinger
Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean-Mignault, Sherbrooke J1E 4K8, Canada.
Antonio
A
Conconi
D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D056565:Sirtuin 2 / Q000235:genetics* / Q000378:metabolism; D016615:Telomere / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D009707:Nucleosomes; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C520769:YKU70 protein, S cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2