TERRA RNA recruits LSD1 to deprotected telomeres. (A) A functional role for the TERRA RNA in the processing of uncapped telomeres, as previously reported (Porro et al. 2014b). TERRA can serve as a scaffold for LSD1–MRE11 associations. (B) Protein constructs used in this study include LSD1 (aa 171–852) and CoREST (aa 286–482 plus 6xHis-tag sequence). LSD1 consists of a SWIRM domain (red), an intertwined monoamine oxidase domain (cyan/blue), and a tower domain (green), based on PDB 2IW5 (Yang et al. 2006). LSD1 biological function requires the presence of CoREST (shown in orange). (C) A GQ RNA is stabilized by specific monovalent ions (including K+ and Na+ denoted as blue spheres). A single GQ RNA unit and a stacked GQ RNA were prepared to investigate binding affinity and specificity of the GQ RNA–LSD1 interaction. The UUAGGG repeat elements of TERRA can form a stable parallel-stranded GQ RNA in vivo (Xu et al. 2010) and a model of the higher order TERRA RNA architecture has been previously demonstrated (Martadinata and Phan 2013).
