biostudies-literature00410Lie TJNIGMS NIH HHS755-62https://www.ebi.ac.uk/biostudies/studies/S-EPMC3104677biostudies-literatureUnknown75(3)The euryarchaeal transcriptional repressor NrpR regulates a variety of nitrogen assimilation genes by 2-oxoglutarate-reversible binding to conserved palindromic operators. The number and positioning of these operators varies among promoter regions of regulated genes, suggesting NrpR can bind in different patterns. Particularly intriguing is the contrast between the nif and glnK(1) promoter regions of Methanococcus maripaludis, where two operators are present but with different configurations. Here we study NrpR binding and regulation at the glnK(1) promoter, where the two operator sequences overlap and occur on opposite faces of the double helix. We find that both operators function in binding, with a dimer of NrpR binding simultaneously to each overlapping operator. We show in vivo that the first operator plays a primary role in regulation and the second operator plays an enhancing role. This is the first demonstration of overlapping operators functioning in Archaea.Molecular microbiologyOverlapping repressor binding sites regulate expression of the Methanococcus maripaludis glnK(1) operon.PMC3104677R01 GM055255R01 GM055255-08GM55255Leigh JANiess UMHaydock AKLie TJHendrickson ELMoore BC41falseOverlapping repressor binding sites regulate expression of the Methanococcus maripaludis glnK(1) operon.The euryarchaeal transcriptional repressor NrpR regulates a variety of nitrogen assimilation genes by 2-oxoglutarate-reversible binding to conserved palindromic operators. The number and positioning of these operators varies among promoter regions of regulated genes, suggesting NrpR can bind in different patterns. Particularly intriguing is the contrast between the nif and glnK(1) promoter regions of Methanococcus maripaludis, where two operators are present but with different configurations. Here we study NrpR binding and regulation at the glnK(1) promoter, where the two operator sequences overlap and occur on opposite faces of the double helix. We find that both operators function in binding, with a dimer of NrpR binding simultaneously to each overlapping operator. We show in vivo that the first operator plays a primary role in regulation and the second operator plays an enhancing role. This is the first demonstration of overlapping operators functioning in Archaea.2010-01-01T00:00:00Z2010 Feb2020-10-31T09:29:09Z2019-03-27T00:42:07ZS-EPMC31046772002566110.1111/j.1365-2958.2009.07016.x