{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T19:27:03Z","timestamp":1789759623884,"version":"4.0.1"},"reference-count":29,"publisher":"Microbiology Society","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2005,6,1]]},"abstract":"The Fe(III)-reducing micro-organism Geobacter sulfurreducens<\/jats:italic> requires an outer-membrane c<\/jats:italic>-type cytochrome, OmcB, for Fe(III) reduction, but a related cytochrome, OmcC, which is 73\u200a% identical to OmcB, is not required. The omcB<\/jats:italic> and omcC<\/jats:italic> genes are part of a tandem chromosomal duplication consisting of two repeated clusters of four genes. The 2\u00b77\u2005kb sequences preceding omcB<\/jats:italic> and omcC<\/jats:italic> are identical with the exception of a single base pair change. Studies that combined genetic, Northern blotting and primer extension analyses demonstrated that both omcB<\/jats:italic> and omcC<\/jats:italic> are transcribed as monocistronic and polycistronic (orf1<\/jats:italic>-orf2<\/jats:italic>-omcB<\/jats:italic>\/omcC<\/jats:italic>) transcripts. All of the promoters for the various transcripts were found to be located within the 2\u00b77\u2005kb identical region upstream of omcB<\/jats:italic> and omcC<\/jats:italic>. The sequences of the promoter regions for the two monocistronic transcripts are identical and equidistant from the omcB<\/jats:italic> or omcC<\/jats:italic> start codons. The promoters for the two polycistronic transcripts, in contrast, are distinct. One is specific for transcription of orf1<\/jats:italic>-orf2<\/jats:italic>-omcB<\/jats:italic> and the other is associated with transcription of orf1<\/jats:italic>-orf2<\/jats:italic>-omcC<\/jats:italic>. Studies with an RpoS-deficient mutant suggested that transcription from all four promoters is RpoS dependent under one or more growth conditions. Deletion of orfR<\/jats:italic>, a gene immediately upstream of orf1<\/jats:italic>-orf2<\/jats:italic>-omcB<\/jats:italic> that encodes a putative transcriptional regulator, significantly lowered the omcB<\/jats:italic> transcription when Fe(III) was the electron acceptor and partially inhibited Fe(III) reduction. In contrast, levels of omcC<\/jats:italic> transcripts were unaffected in the orfR<\/jats:italic> mutant. These results indicate that omcB<\/jats:italic> and omcC<\/jats:italic> operons represent a rare instance in which duplicated operons, located in tandem on the chromosome, have different transcriptional regulation.<\/jats:p>","DOI":"10.1099\/mic.0.27870-0","type":"journal-article","created":{"date-parts":[[2005,6,7]],"date-time":"2005-06-07T19:33:51Z","timestamp":1118172831000},"page":"1761-1767","source":"Crossref","is-referenced-by-count":49,"title":["Regulation of two highly similar genes, omcB and omcC, in a 10\u2005kb chromosomal duplication in Geobacter sulfurreducens"],"prefix":"10.1099","volume":"151","author":[{"given":"Ching","family":"Leang","sequence":"first","affiliation":[{"name":"Department of Microbiology, 203 Morrill Science Center IVN, 639 North Pleasant St, University of Massachusetts at Amherst, Amherst, MA 01003, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Derek R.","family":"Lovley","sequence":"additional","affiliation":[{"name":"Department of Microbiology, 203 Morrill Science Center IVN, 639 North Pleasant St, University of Massachusetts at Amherst, Amherst, MA 01003, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"345","reference":[{"key":"R1","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/0378-1119(95)00108-I","article-title":"Improved antibiotic-resistance gene cassettes and omega elements for Escherichia coli vector construction and in vitro deletion\/insertion mutagenesis","volume":"160","author":"Alexeyev","year":"1995","journal-title":"Gene"},{"key":"R2","doi-asserted-by":"crossref","first-page":"1548","DOI":"10.1128\/AEM.69.3.1548-1555.2003","article-title":"Electricity production by Geobacter sulfurreducens attached to electrodes","volume":"69","author":"Bond","year":"2003","journal-title":"Appl Environ Microbiol"},{"key":"R3","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1126\/science.1066771","article-title":"Electrode-reducing microorganisms that harvest energy from marine sediments","volume":"295","author":"Bond","year":"2002","journal-title":"Science"},{"key":"R4","doi-asserted-by":"crossref","first-page":"3752","DOI":"10.1128\/AEM.60.10.3752-3759.1994","article-title":"Geobacter sulfurreducens sp. nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism","volume":"60","author":"Caccavo","year":"1994","journal-title":"Appl Environ Microbiol"},{"key":"R5","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1038\/416767a","article-title":"Geobacter metallireducens accesses insoluble Fe(III) oxide by chemotaxis","volume":"416","author":"Childers","year":"2002","journal-title":"Nature"},{"key":"R6","doi-asserted-by":"crossref","first-page":"5183","DOI":"10.1128\/AEM.70.9.5183-5189.2004","article-title":"Direct correlation between rates of anaerobic respiration and levels of mRNA for key respiratory genes in Geobacter sulfurreducens","volume":"70","author":"Chin","year":"2004","journal-title":"Appl Environ Microbiol"},{"key":"R7","doi-asserted-by":"crossref","first-page":"3180","DOI":"10.1128\/AEM.67.7.3180-3187.2001","article-title":"Development of a genetic system for Geobacter sulfurreducens","volume":"67","author":"Coppi","year":"2001","journal-title":"Appl Environ Microbiol"},{"key":"R8","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1128\/MMBR.66.4.671-701.2002","article-title":"Regulation of bacterial drug export systems","volume":"66","author":"Grkovic","year":"2002","journal-title":"Microbiol Mol Biol Rev"},{"key":"R9","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/0378-1119(95)00584-1","article-title":"Four new derivatives of the broad-host-range cloning vector pBBR1MCS, carrying different antibiotic-resistance cassettes","volume":"166","author":"Kovach","year":"1995","journal-title":"Gene"},{"key":"R10","doi-asserted-by":"crossref","first-page":"2096","DOI":"10.1128\/JB.185.7.2096-2103.2003","article-title":"OmcB, a c-type polyheme cytochrome, involved in Fe(III) reduction inGeobacter sulfurreducens","volume":"185","author":"Leang","year":"2003","journal-title":"J Bacteriol"},{"key":"R11","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1042\/bj20020597","article-title":"Biochemical and genetic characterization of PpcA, a periplasmic c-type cytochrome in Geobacter sulfurreducens","volume":"369","author":"Lloyd","year":"2003","journal-title":"Biochem J"},{"key":"R12","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1128\/MMBR.55.2.259-287.1991","article-title":"Dissimilatory Fe(III) and Mn(IV) reduction","volume":"55","author":"Lovley","year":"1991","journal-title":"Microbiol Rev"},{"key":"R13","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1128\/9781555818098","article-title":"Fe(III) and Mn(IV) reduction","volume-title":"Environmental Microbe-Metal Interactions","author":"Lovley","year":"2000"},{"key":"R14","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1089\/153623102321112755","article-title":"Analysis of the genetic potential and gene expression of microbial communities involved in the in situ bioremediation of uranium and harvesting electrical energy from organic matter","volume":"6","author":"Lovley","year":"2002","journal-title":"OMICS"},{"key":"R15","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1038\/nrmicro731","article-title":"Cleaning up with genomics: applying molecular biology to bioremediation","volume":"1","author":"Lovley","year":"2003","journal-title":"Nat Rev Microbiol"},{"key":"R16","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1128\/AEM.51.4.683-689.1986","article-title":"Organic matter mineralization with the reduction of ferric iron in anaerobic sediments","volume":"51","author":"Lovley","year":"1986","journal-title":"Appl Environ Microbiol"},{"key":"R17","doi-asserted-by":"crossref","first-page":"1472","DOI":"10.1128\/AEM.54.6.1472-1480.1988","article-title":"Novel mode of microbial energy metabolism: organic carbon oxidation coupled to dissimilatory reduction of iron or manganese","volume":"54","author":"Lovley","year":"1988","journal-title":"Appl Environ Microbiol"},{"key":"R18","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/S0065-2911(04)49005-5","article-title":"Dissimilatory Fe(III) and Mn(IV) reduction","volume":"49","author":"Lovley","year":"2004","journal-title":"Adv Microb Physiol"},{"key":"R19","doi-asserted-by":"crossref","first-page":"2065","DOI":"10.1099\/00221287-147-8-2065","article-title":"Development of improved versatile broad-host-range vectors for use in methylotrophs and other Gram-negative bacteria","volume":"147","author":"Marx","year":"2001","journal-title":"Microbiology"},{"key":"R20","doi-asserted-by":"crossref","first-page":"1967","DOI":"10.1126\/science.1088727","article-title":"& 31 other authors","volume":"302","author":"Methe","year":"2003","journal-title":"Science"},{"key":"R21","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/S0378-1119(00)00071-8","article-title":"PCR-mediated gene replacement in Escherichia coli","volume":"246","author":"Murphy","year":"2000","journal-title":"Gene"},{"key":"R22","doi-asserted-by":"crossref","first-page":"2248","DOI":"10.1128\/AEM.66.5.2248-2251.2000","article-title":"Lack of production of electron-shuttling compounds or solubilization of Fe(III) during reduction of insoluble Fe(III) oxide byGeobacter metallireducens","volume":"66","author":"Nevin","year":"2000","journal-title":"Appl Environ Microbiol"},{"key":"R23","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1080\/01490450252864253","article-title":"Mechanisms for Fe(III) oxide reduction in sedimentary environments","volume":"19","author":"Nevin","year":"2002a","journal-title":"Geomicrobiol J"},{"key":"R24","doi-asserted-by":"crossref","first-page":"2294","DOI":"10.1128\/AEM.68.5.2294-2299.2002","article-title":"Mechanisms for accessing insoluble Fe(III) oxide during dissimilatory Fe(III) reduction byGeothrix fermentans","volume":"68","author":"Nevin","year":"2002b","journal-title":"Appl Environ Microbiol"},{"key":"R25","doi-asserted-by":"crossref","first-page":"5543","DOI":"10.1128\/JB.186.16.5543-5546.2004","article-title":"The RpoS sigma factor in the dissimilatory Fe(III)-reducing bacterium Geobacter sulfurreducens","volume":"186","author":"Nunez","year":"2004","journal-title":"J Bacteriol"},{"key":"R26","volume-title":"Molecular Cloning: a Laboratory Manual","author":"Sambrook","year":"1989"},{"key":"R27","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1016\/0003-2697(85)90442-7","article-title":"& 7 other authors","volume":"150","author":"Smith","year":"1985","journal-title":"Anal Biochem"},{"key":"R28","volume-title":"Transcription Regulation in Prokaryotes","author":"Wagner","year":"2000"},{"key":"R29","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/0378-1119(85)90120-9","article-title":"Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors","volume":"33","author":"Yanisch-Perron","year":"1985","journal-title":"Gene"}],"container-title":["Microbiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.microbiologyresearch.org\/content\/journal\/micro\/10.1099\/mic.0.27870-0?crawler=true","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,11,6]],"date-time":"2020-11-06T18:28:03Z","timestamp":1604687283000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.microbiologyresearch.org\/content\/journal\/micro\/10.1099\/mic.0.27870-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2005,6,1]]},"references-count":29,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2005,6,1]]}},"URL":"https:\/\/doi.org\/10.1099\/mic.0.27870-0","relation":{},"ISSN":["1350-0872","1465-2080"],"issn-type":[{"value":"1350-0872","type":"print"},{"value":"1465-2080","type":"electronic"}],"subject":[],"published":{"date-parts":[[2005,6,1]]}}}