A) Silencing assays for tethered Sir2 constructs. Strains GA-2050 (wt), CSW98 (Δsir2) and CSW157 (Δsir4) expressing lexA-Sir278–562 (pCSW22), lexA-Sir2243–562 (pCSW21), lexA alone (pBTM116H) or Sir3-lexA (pCSW17) were spotted on SC-his (growth) and SC-trp,-his plates (silencing). In the Δsir4 strain, high expression of the lexA-Sir2 constructs caused a slight growth defect, as reported previously [77]. To compensate, the cell density of Δsir4 isolates bearing lexA-Sir2 constructs was concentrated 10-fold before plating. B) Cohesion of HMR circles by lexA-Sir2243–562 in silencing-deficient mutants. Strains CSW18 (wt), CSW42 (Δsir2), CSW85 (Δsir3) and CSW43 (Δsir4) were transformed with pCSW21. C) Cohesion of HMR circles by Sir3-lexA. Strains CSW19 (wt), CSW42 (Δsir2) and CSW85 (Δsir3) and CSW43 (Δsir4) were transformed with a plasmid expressing Sir3-lexA (pCSW14).