Top: Schematic representation of the TEL7L::URA3 reporter used to assay silencing at telomeres. Bottom: wt cells (GA-503) transformed with either an empty plasmid (row 1), plasmid overexpressing wt Sir4 H‑BRCT (row 2), or plasmid overexpressing RKR mutant Sir4 H‑BRCT (row 3). Cells lacking endogenous sir4 (GA-5822) (row 4). Cells were grown in the absence of uracil and plated as 1:5 serial dilutions onto control YPAD or YPAD lacking uracil plates and imaged after 2 days. Top: Schematic representation of the HMR-EΔB::TRP1 reporter gene locus used for assaying silencing at the HMR locus. Bottom: wt cells (GA-485) transformed with plasmids as in panel D. Cells lacking endogenous sir4 (GA-6888) (row 4). Cells were grown in the absence of tryptophan and plated as 1:5 serial dilutions onto YPAD or YPAD lacking tryptophan plates and imaged after 2 days. 