title: A smaller form of the sliding clamp subunit of DNA polymerase III is induced by UV irradiation in Escherichia coli.
abstract: The beta subunit of DNA polymerase III holoenzyme of Escherichia coli is a 40.6-kDa protein that functions as a sliding DNA clamp (Stukenberg, P. T., Studwell-Vaughan, P. S., and O'Donnell, M. (1991) J. Biol. Chem. 266, 11328-11334). It is responsible for tethering the polymerase to DNA and endowing it with the high processivity required for DNA replication. Here and in a companion study (Paz-Elizur, T., Skaliter, R., Blumenstein, S., and Livneh, Z. (1996) J. Biol. Chem. 271, 2482-2490) we report that the dnaN gene, encoding the beta subunit, contains an internal in-frame gene, termed dnaN*, that encodes a smaller form of the beta subunit. The novel 26-kDa protein, termed beta*, is UV-inducible, and when overexpressed from a plasmid under an inducible promoter, it increases up to 6-fold the UV resistance of E. coli cells. These findings suggest that the beta* protein functions in a reaction associated with DNA repair or recovery of DNA replication in UV-irradiated cells.
authors.affiliation: Department of Biochemistry, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Skaliter
authors.forename: T
authors.initials: T
authors.lastname: Paz-Elizur
authors.forename: Z
authors.initials: Z
authors.lastname: Livneh
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004258:DNA Polymerase III / Q000096:biosynthesis* / Q000235:genetics; D004274:DNA, Recombinant; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology / Q000528:radiation effects*; D008969:Molecular Sequence Data; D010957:Plasmids; D014466:Ultraviolet Rays
chemical_list: D004274:DNA, Recombinant; D004258:DNA Polymerase III