Table 3.

In vivo and in vitro termination efficiencies of the λtI⁺ and its λtI deletions quantified by transcripts.

Terminator or deletion	galK RNA level*	% in vivo termination†	% in vitro termination‡
Without terminator	52.0	0	nd
Wild λtI terminator	1.0	98	65
tIΔ3′+32	4.0	92	38
tIΔ3′+22	3.6	93	nd
tIΔ3′·+3	13.4	74	39
tIΔ3′−9	52.1	0	18
tIΔ3′−15	52.3	0	18
tIΔ3′−34	52.3	0	nd
tIΔ5′−106	3.1	94	nd
tIΔ5−92	4.3	92	31
tIΔ5′−64	9.9	81	13
tIΔ5′−37	10.6	80	14
tIΔ5−32	29.2	44	14
tIΔ5′−31	41.1	21	nd

Note: nd, not determined.

^*Measurements are the average of 3 different pairs of autoradiograms in which galK RNA is normalized to β-lactamase RNA levels. pMC and pMS series were used.

^†Percent in vivo termination was calculated by subtracting galK RNA levels for thevarious tI derivatives from the pKG1800 control, lacking a terminator, then dividingby the units found for pKG1800 and multiplying by 100%.

^‡Percent in vitro termination was calculated as follows: (counts per minute of terminated transcript × 100)/(counts per minute of terminated transcript + counts per minute of nonterminated transcript); 1 cpm = 0.0167 Bq. The pBS series was used.