Table 3.

β-Galactosidase production in various strains showing effects of comX mutations on CSP-dependent regulation of transformation genes

Strain	lacZ reporter fusion sites	Phenotype^b	β-Galactosidase activity^a
			Clone	Expt 1		Expt 2		Expt 3		Expt 4
			Clone	−CSP	+CSP	−CSP	+CSP	−CSP	+CSP	−CSP	+CSP
CPM6	comC	WT		330	360	150	150
CPM10	comC	ComX1⁻ComX2⁻	1				150	300	390
			2							240	430
CP1649	comA	ComA⁻		2.2	130	2.3	130
CPM11	comA	ComX1⁻ ComX2⁻ComA⁻	1			2.0	150	2.7	210
			2							0.9	270
CPM3	comX1	WT		0.9	100			3.2	50
CPM16	comX2	WT	1					3.5	130	4.1	190
			2					3.2	140	4.1	180
CPM17	comX1	ComE⁻	1					2.7	2.6	2.5	3.4
			2					3.6	3.5
CPM9	comX2	ComX2⁻	1	8.7	260			3.2	150	4.6	170
			2							2.4	190
CPM4	comX2	ComX1⁻ComX2⁻	1	3.1	570			3.3	330	3.1	390
			2							2.7	390
CPM7	ssb2	WT		0.9	130	2.2	110			1.7	60
CPM12	ssb2	ComX1⁻ComX2⁻	1			1.8	2.0	3.3	3.2
			2							3.9	4.5
CP1548	cglA	CglA⁻		3.4	370		160	3.5	190
CPM13	cglA	ComX1⁻ ComX2⁻CglA⁻	1			1.8	1.8	2.9	2.9
			2							3.9	3.1
CP1601	celB	CelB⁻		1.5	90	1.8		2.5	50
CPM14	celB	ComX1⁻ ComX2⁻CelB⁻	1			2.2	2.1	2.9	3.2
			2							3.5	4.4
CP1506	cflA	CflA⁻		0.5	90		70
CPM15	cflA	ComX1⁻ ComX2⁻CflA⁻	1				1.6	3.0	3.2
			2							3.7	4.1
CP1250	None	WT		0.4	1.5			2.9	2.8	3.1	2.5

↵a Two independent clones of each strain were grown in CAT containing 6 mM HCl to an OD₅₅₀ of 0.05 in several experiments. After 1 ml of culture was either not treated (−CSP) or treated (+CSP) with CSP and NaOH, incubation was continued for 40 min. Enzyme activity in crude cell extract at 40 min was measured by the ONPG assay and is expressed in Miller units (30).
↵b WT, wild type.