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The damage-inducible UmuD' and UmuC proteins are required for most SOS mutagenesis in Escherichia coli. Our recent assay to reconstitute this process in vitro, using a native UmuD'(2)C complex, revealed that the highly purified preparation contained DNA polymerase activity. Here we eliminate the possibility that this activity is caused by a contaminating(More)
Most SOS mutagenesis in Escherichia coli is dependent on the UmuD and UmuC proteins. Perhaps as a consequence, the activity of these proteins is exquisitely regulated. The intracellular level of UmuD and UmuC is normally quite low but increases dramatically in lon- strains, suggesting that both proteins are substrates of the Lon protease. We report here(More)
For life to be sustained, mistakes in DNA repair must be tolerated when damage obscures the genetic information. In bacteria such as Escherichia coli, DNA damage elicits the well regulated 'SOS response'. For the extreme case of damage that cannot be repaired by conventional enzymes, there are proteins that allow the replication of DNA through such lesions,(More)
We have developed a series of plasmid vectors for the soluble expression and subsequent purification of recombinant proteins that have historically proven to be extremely difficult to purify from Escherichia coli. Instead of dramatically overproducing the target protein, it is expressed at a low basal level that facilitates the correct folding of the(More)
The Saccharomyces cerevisiae RAD30 gene encodes DNA polymerase eta. Humans possess two Rad30 homologs. One (RAD30A/POLH) has previously been characterized and shown to be defective in humans with the Xeroderma pigmentosum variant phenotype. Here, we report experiments demonstrating that the second human homolog (RAD30B), also encodes a novel DNA polymerase(More)
replenishment of nutrients by fertiliser and oversowing, is topsoil nutrient decline over time accompanied by a decline in vegetation cover, and displacement of native by exotic species (Treskonova 1991), as has been demonstrated in other grasslands exposed to novel grazing by large herbivores (Milchunas and Lauenroth 1993). Although some researchers have(More)
The Saccharomyces cerevisiae RAD30 gene encodes DNA polymerase ␩. Humans possess two Rad30 homologs. One (RAD30A/POLH) has previously been characterized and shown to be defective in humans with the Xeroderma pigmentosum variant phenotype. Here, we report experiments demonstrating that the second human homolog (RAD30B), also encodes a novel DNA polymerase(More)
DNA damage-inducible mutagenesis in Escherichia coli is largely dependent upon the activity of the UmuD (UmuD') and UmuC proteins. The intracellular level of these proteins is tightly regulated at both the transcriptional and the posttranslational levels. Such regulation presumably allows cells to deal with DNA damage via error-free repair pathways before(More)
Human DNA polymerase iota (poliota) is a Y-family polymerase whose cellular function is presently unknown. Here, we report on the ability of poliota to bypass various stereoisomers of benzo[a]pyrene (BaP) diol epoxide (DE) and benzo[c]phenanthrene (BcPh) DE adducts at deoxyadenosine (dA) or deoxyguanosine (dG) bases in four different template sequence(More)
DNA polymerase iota (pol iota) is one of several recently discovered DNA polymerases in mammalian cells whose function is unknown. We report here that human pol iota has an intrinsic 5'-deoxyribose phosphate (dRP) lyase activity. In reactions reconstituted with uracil-DNA glycosylase (UDG), apurinic/apyrimidinic (AP) endonuclease and DNA ligase I, pol iota(More)