Copyright information:Taken from "An SOS-regulated operon involved in damage-inducible mutagenesis in "Nucleic Acids Research 2005;33(8):2603-2614.Published online 10 May 2005PMCID:PMC1092274.© The Author 2005. Published by Oxford University Press. All rights reserved () Schematic diagram for this operon indicating the position of the oligonucleotides (small arrows) used in the RT–PCR strategy to detect the co-expression of the three genes. Template RNA was extracted from exponentially growing cells, both from non-irradiated cultures and from cultures irradiated with 60 J/m of UV and recovered after 45 min. The RT–PCR products were visualized after electrophoresis in 1% agarose gel stained with ethidium bromide. () Expression of and promoters in transcriptional fusions with the gene. β-Galactosidase activity was measured 90 min after irradiation with UV light, both in the wild-type and strains.