{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:09:30Z","timestamp":1792786170356,"version":"4.5.0"},"reference-count":28,"publisher":"Microbiology Society","issue":"10","license":[{"start":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T00:00:00Z","timestamp":1791417600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Deanship of Scientific Research, King Saud University","award":["ORF-2026-1475"],"award-info":[{"award-number":["ORF-2026-1475"]}],"id":[{"id":"https:\/\/ror.org\/02f81g417","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,8]]},"abstract":"<jats:p>\n                    Capsular polysaccharides are key virulence determinants in extraintestinal pathogenic\n                    <jats:italic>Escherichia coli<\/jats:italic>\n                    , protecting bacteria from host immune defences while modulating interactions with host tissues. In group 2 capsule gene clusters, transcription of region 1 genes required for capsule export is controlled by a complex regulatory region (PR1) containing three tandem promoters (PR1-1, PR1-2 and PR1-3).\n                  <\/jats:p>\n                  <jats:p>\n                    In this study, targeted mutations were introduced into the \u221210 elements of each PR1 promoter in the uropathogenic strain UTI89. Transcriptional output from the PR1 region was assessed using a chromosomal PR1\u2013\n                    <jats:italic>lacZ<\/jats:italic>\n                    fusion, and capsule expression was evaluated by K1 bacteriophage sensitivity assays, flow cytometry and immunofluorescence microscopy. Growth in Lysogeny Broth medium demonstrated that all three promoters contributed to capsule expression\n                    <jats:italic>in vitro,<\/jats:italic>\n                    with expression from both PR1-2 and PR1-3 being dependent on a functional upstream PR1-1.\n                  <\/jats:p>\n                  <jats:p>In contrast, infection of PD07i bladder epithelial cells revealed a distinct regulatory pattern in which, following invasion, intracellular capsule expression was restored in the absence of PR1-1 and PR1-2, indicating that PR1-3 was sufficient for capsule induction within bladder cells. The presence of a predicted binding site for the oxygen-responsive regulator fumarate and nitrate reduction regulatory protein near PR1-3 suggests a possible mechanism for intracellular activation of PR1-3 under microaerobic host conditions in the absence of a functional PR1-1 promoter.<\/jats:p>\n                  <jats:p>Together, these findings reveal a niche-dependent, multi-promoter regulatory architecture that enables adaptive control of capsule expression during infection.<\/jats:p>","DOI":"10.1099\/mic.0.001783","type":"journal-article","created":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T16:17:05Z","timestamp":1791476225000},"source":"Crossref","is-referenced-by-count":0,"title":["In vitro and in vivo functional roles of three region 1 promoters in Escherichia coli K1 capsule gene cluster"],"prefix":"10.1099","volume":"172","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7043-3915","authenticated-orcid":false,"given":"Esraa","family":"Aldawood","sequence":"first","affiliation":[{"name":"Department of Clinical Laboratory Science, College of Applied Medical Science, King Saud University, P. O. Box 10219, Riyadh 11433, Kingdom of Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0662-0214","authenticated-orcid":false,"given":"Ian S.","family":"Roberts","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"345","reference":[{"key":"R1","doi-asserted-by":"publisher","DOI":"10.3390\/pathogens10111355"},{"key":"R2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-023-39052-w"},{"key":"R3","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2022.858767"},{"key":"R4","doi-asserted-by":"publisher","DOI":"10.1016\/S0065-2164(08)00601-1"},{"key":"R5","doi-asserted-by":"publisher","DOI":"10.1128\/jb.178.11.3212-3220.1996"},{"key":"R6","doi-asserted-by":"publisher","DOI":"10.1128\/jb.178.22.6466-6474.1996"},{"key":"R7","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-017-17891-0"},{"key":"R8","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.1997.4241780.x"},{"key":"R9","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.1999.01276.x"},{"key":"R10","doi-asserted-by":"publisher","DOI":"10.1128\/JB.01388-08"},{"key":"R11","doi-asserted-by":"publisher","DOI":"10.1128\/JB.182.10.2741-2745.2000"},{"key":"R12","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M703465200"},{"key":"R13","article-title":"Characterising the functional roles of the three promoters in region one of the escherichia coli group 2 capsule gene cluster (PhD thesis)","author":"Aldawood","year":"2019"},{"key":"R14","doi-asserted-by":"publisher","DOI":"10.1111\/mmi.13987"},{"key":"R15","doi-asserted-by":"publisher","DOI":"10.1128\/mBio.01558-17"},{"key":"R16","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00188-15"},{"key":"R17","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2180-9-252"},{"key":"R18","volume-title":"Experiments in Molecular Genetics","author":"Miller","year":"1972"},{"key":"R19","article-title":"NZB mouse system for production of monoclonal antibodies to weak bacterial antigens: Isolation of an IgG antibody to the polysaccharide capsules of Escherichia coli K1 and group B meningococci (bacterial capsules\/N-acetylneuraminic acid\/ELISA)","author":"Frosch","year":"1985"},{"key":"R20","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.micro.50.1.285"},{"key":"R21","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmb.2003.07.017"},{"key":"R22","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pgen.0020185"},{"key":"R23","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.2000.02087.x"},{"key":"R24","doi-asserted-by":"publisher","DOI":"10.1038\/nrmicro787"},{"key":"R25","doi-asserted-by":"publisher","DOI":"10.1016\/j.acra.2008.04.013"},{"key":"R26","doi-asserted-by":"publisher","DOI":"10.3390\/ijms18102077"},{"key":"R27","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.01260-09"},{"key":"R28","article-title":"Regulation of transcription of the Escherichia coli group 2 capsule gene clusters","author":"Aal Owaif","year":"2016"}],"container-title":["Microbiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.microbiologyresearch.org\/content\/journal\/micro\/10.1099\/mic.0.001783?crawler=true&mimetype=application\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T16:17:06Z","timestamp":1791476226000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.microbiologyresearch.org\/content\/journal\/micro\/10.1099\/mic.0.001783"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,8]]},"references-count":28,"journal-issue":{"issue":"10","published-print":{"date-parts":[[2026,10,8]]}},"URL":"https:\/\/doi.org\/10.1099\/mic.0.001783","relation":{},"ISSN":["1350-0872","1465-2080"],"issn-type":[{"value":"1350-0872","type":"print"},{"value":"1465-2080","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,8]]}}}