title: Functional identification in Lactobacillus reuteri of a PocR-like transcription factor regulating glycerol utilization and vitamin B12 synthesis.
abstract: BACKGROUND
  Lactobacillus reuteri harbors the genes responsible for glycerol utilization and vitamin B12 synthesis within a genetic island phylogenetically related to gamma-Proteobacteria. Within this island, resides a gene (lreu_1750) that based on its genomic context has been suggested to encode the regulatory protein PocR and presumably control the expression of the neighboring loci. However, this functional assignment is not fully supported by sequence homology, and hitherto, completely lacks experimental confirmation.
  
  
  RESULTS
  In this contribution, we have overexpressed and inactivated the gene encoding the putative PocR in L. reuteri. The comparison of these strains provided metabolic and transcriptional evidence that this regulatory protein controls the expression of the operons encoding glycerol utilization and vitamin B12 synthesis.
  
  
  CONCLUSIONS
  We provide clear experimental evidence for assigning Lreu_1750 as PocR in Lactobacillus reuteri. Our genome-wide transcriptional analysis further identifies the loci contained in the PocR regulon. The findings reported here could be used to improve the production-yield of vitamin B12, 1,3-propanediol and reuterin, all industrially relevant compounds.
authors.affiliation: Center for Integrative Bioinformatics, Vrije Universiteit Amsterdam, Boelelaan1085, 1081 HV Amsterdam, The Netherlands.
authors.forename: Filipe
authors.initials: F
authors.lastname: Santos
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Spinler
authors.forename: Delphine M A
authors.initials: DM
authors.lastname: Saulnier
authors.forename: Douwe
authors.initials: D
authors.lastname: Molenaar
authors.forename: Bas
authors.initials: B
authors.lastname: Teusink
authors.forename: Willem M
authors.initials: WM
authors.lastname: de Vos
authors.forename: James
authors.initials: J
authors.lastname: Versalovic
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hugenholtz
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000145:classification / Q000378:metabolism*; D020869:Gene Expression Profiling; D056426:Genetic Loci; D005985:Glyceraldehyde / Q000031:analogs & derivatives / Q000378:metabolism; D005990:Glycerol / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D052200:Limosilactobacillus reuteri / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011407:Propane / Q000378:metabolism; D011409:Propylene Glycols / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000145:classification / Q000378:metabolism*; D014805:Vitamin B 12 / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D011409:Propylene Glycols; D014157:Transcription Factors; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; C041787:1,3-propanediol; D014805:Vitamin B 12; D005990:Glycerol; D011407:Propane