FIG. 8.
Overexpression of full-length Sir3p restores silencing in a strain that overexpress full-length Sir4p. The strain UCC3107, which carries ADE2 adjacent to the VR telomere, was transformed with plasmids as indicated as well as a second control plasmid. The control plasmids are the backbone vector without SIR gene inserts, namely, pAAH5 and p2HG (see Materials and Methods). The plasmids with SIR gene inserts are pADH-SIR4 and pGPD-SIR3. Colonies (two independent transformants in each case) were streaked onto medium lacking histidine and leucine to ensure maintenance of the plasmids and allowed to grow for 3 to 5 days at 30°C. Following incubation, the plates were stored at 4°C for 1 week to enhance the pigmentation of the cells.