Table 3. Other factors that attenuate the Rex phenotype.

Mutation	Rex plasmida	Relative efficiency of platingb
		T4 (rII+)	T4rII (rII−)
–	+	1.0	<3.0 × 10−7
	–	1.0	1.0
ΔmglA	+	7.0 × 10−2	<3.0 × 10−7
	–	0.7	0.7
ΔmglB	+	0.7	<3.0 × 10−7
	–	0.7	1.0
ΔmglC	+	0.1	2.0 × 10−5
	–	0.7	1.0
ΔgalM	+	1.0	<3.0 × 10−7
	–	0.6	1.0
ΔgalK	+	7.0 × 10−2	<3.0 × 10−7
	–	0.6	1.0
ΔgalT	+	8.0 × 10−2	<3.0 × 10−7
	–	0.7	1.0
ΔgalE	+	1.0 × 10−2	<3.0 × 10−7
	–	1.0	1.2
ΔgalU	+	<3.0 × 10−7	<3.0 × 10−7
	–	<3.0 × 10−7	<3.0 × 10−7
ΔgalF	+	1.0	<3.0 × 10−7
	–	0.7	1.0
ΔgalP	+	1.0	<3.0 × 10−7
	–	0.7	1.0
ΔgalS	+	0.3	<3.0 × 10−7
	–	0.7	1.0
ΔgalR	+	1.0	<3.0 × 10−7
	–	0.7	1.0
ΔrpoS	+	<3.0 × 10−7	<3.0 × 10−7
	–	0.7	0.7
ΔrssB	+	0.5	3.0 × 10−3
	–	1.0	1.0
ΔrssA	+	3.0 × 10−3	0.2
	–	1.0	1.0
ΔiraP	+	3.0 × 10−2	<3.0 × 10−7
	–	1.0	1.0
ΔiraM	+	0.5	<3.0 × 10−7
	–	1.0	1.0
ΔiraD	+	0.5	<3.0 × 10−3
	–	1.0	1.0

^aThe Rex⁺ plasmid is pHA1, a pUC-derived high-copy plasmid carrying the P_M-cI-rexA-rexB-t_imm cassette.

^bAll assayed strains are isogenic derivatives of Keio collection wild-type BW25113. EOPs are determined by dividing the number of plaques for the sample by the number of plaques on the 100% control. EOPs of T4/T4rII were determined using BW25113 as the 100% control for T4rII plating and BW25113[pHA1] as the 100% control for Rex activity. All results represent the average of three independent plating assays. Strains (rex⁺) attenuated for Rex activity showed pinpoint plaques compared to rex⁻ counterparts.