TABLE 3.

Activities of the IKe gene V and gene VII initiation sites

Plasmida	β-Galactosidase activity		Relative lacZ-specific mRNA level (%)d
	Ub	%c
pSM5	46,400	100.0	100
pSM7	260	0.6	40
pSM5-7	630	1.3	60

^aPlasmids in this table and Fig. 3, 6, and 7 were harbored in the lac deletion strain DS70. 

^bo-Nitrophenyl absorbancy units at A₄₂₀/min per A₆₀₀ unit of cells (27). Background values for DS70 bearing the parent vector lacking an IKe insert (pKC8) have been subtracted. The values are the average of at least four determinations. 

^cExpressed relative to that of pSM5. 

^dLevels of [³H]uridine-labelled lacZ-specific RNA, determined as described in Materials and Methods, are expressed relative to that of pSM5.