TABLE 3.

β-Galactosidase activity assay of REB1′-lacZ reporter genes^a

Strain	REB1 siteb	Result in:
		DEX medium		GAL medium
		Activity	% of wild typec	Activity	% of wild typec
WY83	ABC	2.52 ± 0.08	100	0.67 ± 0.02	100
WY85	AC	1.96 ± 0.09	78	0.54 ± 0.02	81
WY84	BC	1.07 ± 0.02	42	0.36 ± 0.01	54
WY86	C	0.09 ± 0.00	4	0.05 ± 0.00	8
WY90	AB	4.38 ± 0.08	174	3.43 ± 0.05	512
WY105	ABC+75	4.11 ± 0.09	163	2.70 ± 0.08	403
WY102	A	2.12 ± 0.00	84	2.00 ± 0.04	286
WY103	B	1.04 ± 0.03	41	2.18 ± 0.03	325
WY101	Null	0.06 ± 0.00	2	0.05 ± 0.01	8
WY123	Vector	0.04 ± 0.00	1	0.04 ± 0.00	6

^aStrains with a single REB1′-lacZ reporter gene integrated into the URA3 locus were used for the β-galactosidase activity assay as described in Materials and Methods. At least two independent clones with an integrated reporter gene of each construct were assayed. Triplicate data from each clone were used to average the activity; the standard error for each construct was <5%. The entire set of experiments was reproduced at least twice in Ura⁻, His⁻ dropout medium containing either 2% dextrose (DEX) or 2% galactose (GAL) as the sole carbon source. Reb1p binding sites are indicated to represent the differences between the otherwise isogenic strains. Null is a construct with all three sites mutated; vector is a construct with no promoter in front of the lacZ sequences. 

^bReb1p binding sites in the REB1′-lacZ reporter genes. 

^cThe activity of strains with wild-type Reb1p binding sites is used as 100% in the DEX and GAL media.