title: Molecular cloning and characterization of hetR genes from filamentous cyanobacteria.
abstract: HetR, a serine type protease, plays an important role in heterocyst differentiation in filamentous cyanobacteria. We isolated and sequenced the hetR genes from different heterocystous and filamentous nonheterocystous cyanobacteria. The hetR gene in the heterocyst forming Anabaena variabilis ATCC 29413 FD was interrupted by interposon mutagenesis (mutant strain WSIII8). This mutant does not form heterocysts and shows no diazotrophic growth under aerobic conditions. However, under anaerobic N(2)-fixing conditions, the WSIII8 cells are able to grow, and high nitrogenase (Nif2) activity is detectable. Nif2 expression was demonstrated in each vegetative cell of the filament by immunolocalization 4 h after nitrogen step-down.
authors.affiliation: Botanisches Institut, Universität Bonn, Karlrobert-Kreiten-Strasse 13, 53115 Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schiefer
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schütz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hachtel
authors.forename: Thomas
authors.initials: T
authors.lastname: Happe
mesh_terms: D000595:Amino Acid Sequence; D017033:Anabaena / Q000166:cytology / Q000201:enzymology; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; C067403:HetR protein, Bacteria; D009591:Nitrogenase