Table 3.

Steady-state levels of E. coli Pols expressed from the chromosome or plasmids

Polyclonal antibody specificity	Molecules/cell of respective DNA Pol as a function of SOS statusa
	SOS repressed			SOS induced
	Chromosome	Chromosome plus plasmid	Plasmid aloneb	Chromosome	Chromosome plus plasmid	Plasmid alone
Pol I	588 ± 60	3,265 ± 959	≈2,677	495 ± 107	4,124 ± 1,700	≈3,629
Pol II	75 ± 44	1,819 ± 786	≈1,744	1,073 ± 486	8,648 ± 328	≈7,575
Pol IV	≥156	1,233 ± 224	≈1,077	1,161 ± 155	4,944 ± 1,153	≈3,783
Pol Vc	NDd	ND	ND	60	300	≈240

^aSteady-state levels of each Pol present under SOS-repressed (lexA⁺) and SOS-induced [lexA51(Def)] states are indicated. Results shown represent the averages of triplicates ± standard deviations.

^bThe approximate level of each Pol expressed from the respective plasmid was calculated by subtracting the level observed for the strain bearing the Pol-expressing plasmid from the level observed for the same strain bearing the control plasmid.

^cValues shown for Pol V (UmuD′₂C) are from reference 40.

^dND, none detected.