title: Mre11 modulates the fidelity of fusion between short telomeres in human cells.
abstract: The loss of telomere function can result in the fusion of telomeres with other telomeric loci, or non-telomeric double-stranded DNA breaks. Sequence analysis of fusion events between short dysfunctional telomeres in human cells has revealed that fusion is characterized by a distinct molecular signature consisting of extensive deletions and micro-homology at the fusion points. This signature is consistent with alternative error-prone end-joining processes. We have examined the role that Mre11 may play in the fusion of short telomeres in human cells; to do this, we have analysed telomere fusion events in cells derived from ataxia-telangiectasia-like disorder (ATLD) patients that exhibit hypomorphic mutations in MRE11. The telomere dynamics of ATLD fibroblasts were indistinguishable from wild-type fibroblasts and they were proficient in the fusion of short telomeres. However, we observed a high frequency of insertion of DNA sequences at the fusion points that created localized sequence duplications. These data indicate that Mre11 plays a role in the fusion of short dysfunctional telomeres in human cells and are consistent with the hypothesis that as part of the MRN complex it serves to stabilize the joining complex, thereby controlling the fidelity of the fusion reaction.
authors.affiliation: Department of Pathology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: Maira
authors.initials: M
authors.lastname: Tankimanova
authors.forename: Rebecca
authors.initials: R
authors.lastname: Capper
authors.forename: Boitelo T
authors.initials: BT
authors.lastname: Letsolo
authors.forename: Jan
authors.initials: J
authors.lastname: Rowson
authors.forename: Rhiannon E
authors.initials: RE
authors.lastname: Jones
authors.forename: Bethan
authors.initials: B
authors.lastname: Britt-Compton
authors.forename: A Malcolm R
authors.initials: AM
authors.lastname: Taylor
authors.forename: Duncan M
authors.initials: DM
authors.lastname: Baird
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D000076228:MRE11 Homologue Protein; D009154:Mutation; D012091:Repetitive Sequences, Nucleic Acid; D017384:Sequence Deletion; D016615:Telomere / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; D000076228:MRE11 Homologue Protein