TABLE 4.

Effects of srb10Δ, srb11Δ, and ctk1Δ on repression of CYC1-lacZ by LexA-Mig1^a

Protein	Genotype	β-Gal activity			Fold repression
		−LexAop	+1 LexAop	+4 LexAop	1op	4op
Expt Ab
LexA87	WT	76	78	ND	1.0	ND
	srb11Δ	199	148	ND	1.3	ND
LexA87-Mig1	WT	106	6.6	ND	16	ND
	srb11Δ	124	21	ND	5.9	ND
Expt Bc
LexA	WT	91	66	63	1.4	1.4
	srb10Δ	105	74	73	1.4	1.4
LexA-Mig1	WT	111	19	16	5.8	6.9
	srb10Δ	86	35	21	2.5	4.1
Expt Cd
LexA87	WT	77	51	46	1.5	1.7
	ctk1Δ	106	72	58	1.5	1.8
LexA87-Mig1	WT	99	6.3	2.8	16	35
	ctk1Δ	144	26	14	5.5	10

^aPairs of isogenic strains were cotransformed with plasmids expressing fusion proteins and CYC1-lacZ reporter plasmids carrying zero, one, or four LexA operators 5′ to the UAS (Fig. 1). Fold repression for both one-operator (1op) and four-operator (4op) reporters is relative to the operator-less reporter. ND, not determined. 

^bThe strains were MCY3647 and MCY3644, and the plasmids were pSH2-1 or pLexA-Mig1. β-Galactosidase (β-Gal) activity was assayed in permeabilized cells. Values are averages for three independent transformants. Standard errors were <20%. 

^cThe strains were MCY3661 and MCY3662, and the plasmids were pBTM116 and pSK101. β-Galactosidase activity was assayed in protein extracts. Values are averages for five transformants. Standard errors were <12%. 

^dSame as described for experiment B, except that the strains were MCY3661 and MCY3664 and the plasmids were pSH2-1 or pLexA-Mig1. Standard errors were <14%.