Table 2. RecX alone, or in concert with RecO or RecF, plays an important role in chromosomal and plasmid transformation.

Strain	% Chromosomal transformationa	% Plasmid Transformationb
rec +	100 (5.7×10−3)	100 (4.7×10−5)
recF15 c	71.4	96.2
ΔrecR c	69.0	94.1
ΔrecO c	58.2	3.2
recX342c	60.9	93
recX342 ΔrecO c	<0.1	0.1
recX342 ΔrecR c	<0.1	0.9
recX342 recF15 c	<0.1	<0.1
ΔrecA c	<0.01	97.4
ΔrecX	0.5	1.8
ΔrecX ΔrecA	<0.01	57
ΔrecX ΔrecO	<0.1	<0.1
ΔrecX recF15	<0.1	<0.1

The metB5 locus contains a single point mutation.

^aThe yield of met ⁺ transformants (SB19 DNA, chromosomal transformation) and

^bkanamycin resistant transformants (pUB110, plasmid transformation) was corrected for DNA uptake and cell viability, and the values obtained normalized relative to that of the rec ⁺ strain, taken as 100. Between parentheses is included the number of transformants/cell.

^cThe transformation frequencies of rec ⁺, recF15, ΔrecR, ΔrecO, recX342 (previously termed recH342), recX342 ΔrecR, recX342 recF15, recX342 ΔrecO, recX342 ΔrecR and ΔrecA cells were reported elsewhere [13], [15], [16], [52] and determined here for direct comparison. The results are the average of at least three independent experiments and are within a 10% standard error.