TABLE 4.

Sir3N and Sir3C expression in trans complements a sir3::TRP1 allele^a

Strain	Relevant genotype	Plasmids	Mating efficiency (%)b
UCC3107	SIR3	Control	90 (8.2 × 10−1)
		pADH-SIR3N	91 (8.3 × 10−1)
		pADH-SIR3C	103 (9.4 × 10−1)
		pADH-SIR3N + pADH-SIR3C	95 (8.7 × 10−1)
		pADH-SIR3	100 (9.1 × 10−1)
GA822	sir::TRP1	Control	<0.002 (<2 × 10−5)
		pADH-SIR3N	<0.004 (<4 × 10−5)
		pADH-SIR3C	<0.003 (<3 × 10−5)
		pADH-SIR3N + pADH-SIR3C	0.2 (1.9 × 10−3)
		pADH-SIR3	100 (9.1 × 10−1)

^aHost strains UCC3107 and GA822, which are isogenic and Mata, were transformed with plasmids as indicated as well as a second control plasmid. Thus, all the strains contained two plasmids and mating was performed under selective conditions. The control plasmids are the backbone vectors without SIR3 gene inserts, namely, pAAH5 and p423ADH. The control contained both vectors. Plasmids with SIR3 inserts are pADH-SIR3N, pADH-SIR3C (also called pMG17), and pADH-SIR3 (pA-SIR3 [26]) (see Materials and Methods for a description of all plasmids). Mating efficiencies were determined by a quantitative mating assay as described in Materials and Methods. 

^bActual measured values are shown in parentheses.