TABLE 3.

Summary of constitutive mutants

Functional group	Straina	No. of insertionsb	Assay resultsc		Functional or putative functiond	Functional reference	Constitutive reference
			I	II
Replication, recombination, and repair	dam mutant	3	•	•	DNA adenine methylase	61	83, 84, 89
	dnaQ mutant	2	○	•	Epsilon subunit of DNA polymerase III (3′-5′ exonuclease)	50	89, 100
	polA mutant	1	•	•	DNA polymerase I	50	5, 89
	recG mutant	4	•	•	Branch-specific helicase or fork reversal	67	2, 56
	recN mutant	1	•		Recombination and repair gene	85	14, 27, 99
	rep mutant	7	•		Helicase	58	81, 105
	ruvA mutant	3	•	○	Holiday junction helicase (branch migration)	108	2
	ruvB mutant	2	•	○	Holiday junction helicase (branch migration)	108	2e
	ruvC mutant	2	•	○	Holiday junction endonuclease	108	2, 55
	uvrD mutant	2	•	•	DNA-dependent helicase II	32	6, 81, 89
Chromosome dimer resolution	ftsK mutant	14	•	•	Cell division protein or SpoIIIa-like function	24, 28	54
	xerC mutant	8	•	•	Site-specific recombinase	44	40
	xerD mutant	7	•	•	Site-specific recombinase	44	40
	yncD yddW mutantf	1	•	○	Putative outer membrane receptor for iron transport or putative lipoprotein	9	This work
Transcription and transcription regulation	lexA mutant	2	•	•	Global regulator (repressor) for SOS regulon	32	73
	rpoZ mutant	1	•	•	RNA-polymerase subunit omega (polar on recG?)	12	This work
	spoT mutant	6	•	•	ppGpp synthetase (polar on recG?)	12	This work
Nucleoside metabolism	dcd mutant	1	•	•	2′-Deoxycytosine deaminase	75	This work
	folA mutant	1	•		Dihydrofolate reductase	36	This work
	folK mutant	2	○	•	6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase	36	This work
	purA mutant	1		○	Adenylosuccinate synthase	110	This work
	purE mutant	1	○		Phosphoribosylaminoimidazole carboxylase	110	This work
	purF mutant	2	•	•	Glutamine phosphoribosylpyrophosphate amidotransferase	110	This work
	purL mutant	1	○		Phosphoribosylformylglycinamide synthase	110	This work
	thyA mutant	1	•		Thymidylate synthase	75	1g
Membrane structure/function	acrB mutant	14		○	Drug efflux pump	76	This work
	cvpA mutant	1	•	○	Colicin V production protein (polar on purF?)	29, 30	This work
	dsbB mutant	1		○	Disulfide oxidoreductase	46	This work
	ompA mutant	1		○	Outer membrane protein A	76	This work
	tolC mutant	9		○	Channel-tunnel spanning the outer membrane and periplasm	76	This work
Miscellaneous	arpB mutant	1	○	○	Putative regulatory protein with ankyrin repeats	9	This work
	damX mutant	4	•	•	Overproduction interferes with cell division (polar on dam?)	57, 59	This work
	ftsE mutant	1	○	○	ABC transporter? Salt transport?	22, 34	This work
	ftsX mutant	3	•	○	ABC transporter? Salt transport?	22, 34	This work
	rluD ecfD mutanth	1		○	Pseudouridylate synthase; null mutants grow poorly or putative lipoprotein regulated by sigma E	9, 21, 79, 87	This work
							This work
	tdcE mutant	2	•	•	Threonine dehydratase	41	This work
	tynA mutant	1	•	•	Tyramine oxidase	74	This work
	yebC mutant	1	○	•	Putative membrane protein (polar on ruvC?)	4, 9	This work
	yehB mutant	1	○	○	Putative outer membrane export usher protein	9	This work
	yejM mutant	1		○	Putative sulfatase	9	This work
	yfgM mutant	1		○	Putative N-terminal transmembrane domain	9	This work
	yhcB mutant	1	○	○	Conserved bacterial protein of unknown function	9	This work

^aAlternate gene names: arpB, b1720/b1721; ecfD, b2595; envC, yibP; rluD, sfhB; yfgL, b2512; yfgM, b2513; yncD, b1451; yddW, b1491.

^bNumber of independent insertions isolated in each gene. Single hits were confirmed by P1 transduction.

^cPerformance of transposon insertion mutant strains in quantitative assays. I, β-galactosidase assay; II, RecA Western blot assay. Open circles indicate those strains whose assay results exceeded that of the wild type by more than 1 standard deviation; closed circles indicate those strains whose assay results were at least twice as high as wild-type levels.

^dFunctions according to the NCBI website (http://www.ncbi.gov).

^eAlthough ruvB mutants were not directly assayed in the cited study, we assume they are SOS constitutive since RuvAB acts as a complex.

^fThis insertion mutant has two transposons (see text).

^gthyA mutants have never been assayed for the SOS constitutive phenotype; however, this review suggests that they are SOS constitutive based on their phenotypes.

^hThe transposon insertion in this strain is located between the two genes.