title: AguR, a Transmembrane Transcription Activator of the Putrescine Biosynthesis Operon in Lactococcus lactis, Acts in Response to the Agmatine Concentration.
abstract: Dairy industry fermentative processes mostly use Lactococcus lactis as a starter. However, some dairy L. lactis strains produce putrescine, a biogenic amine that raises food safety and spoilage concerns, via the agmatine deiminase (AGDI) pathway. The enzymatic activities responsible for putrescine biosynthesis in this bacterium are encoded by the AGDI gene cluster. The role of the catabolic genes aguB, aguD, aguA, and aguC has been studied, but knowledge regarding the role of aguR (the first gene in the cluster) remains limited. In the present work, aguR was found to be a very low level constitutively expressed gene that is essential for putrescine biosynthesis and is transcribed independently of the polycistronic mRNA encoding the catabolic genes (aguBDAC). In response to agmatine, AguR acts as a transcriptional activator of the aguB promoter (PaguB), which drives the transcription of the aguBDAC operon. Inverted sequences required for PaguB activity were identified by deletion analysis. Further work indicated that AguR is a transmembrane protein which might function as a one-component signal transduction system that senses the agmatine concentration of the medium and, accordingly, regulates the transcription of the aguBDAC operon through a C-terminal cytoplasmic DNA-binding domain typically found in LuxR-like proteins.
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Linares
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Del Rio
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Redruello
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: Victor
authors.identifier: http://orcid.org/0000-0002-7613-3745
authors.initials: V
authors.lastname: Ladero
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: M Cruz
authors.initials: MC
authors.lastname: Martin
authors.affiliation: Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
authors.forename: Anne
authors.initials: A
authors.lastname: de Jong
authors.affiliation: Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
authors.forename: Oscar P
authors.initials: OP
authors.lastname: Kuipers
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Fernandez
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Villaviciosa, Spain maag@ipla.csic.es.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Alvarez
mesh_terms: D000376:Agmatine / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*; D009876:Operon; D011700:Putrescine / Q000096:biosynthesis; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D015534:Trans-Activators; D000376:Agmatine; D011700:Putrescine