title: Cloning and sequencing of the nitrate transport system from the thermophilic, filamentous cyanobacterium Phormidium laminosum: comparative analysis with the homologous system from Synechococcus sp. PCC 7942.
abstract: A genomic region from the filamentous, thermophilic non-N2-fixing cyanobacterium Phormidium laminosum was cloned and sequenced. It includes the nitrite reductase gene (nirA) and three other genes (nrtA, B and C) located downstream of nirA, which are related to the nitrate transport system on the basis of a comparison with the homologous system from Synechococcus sp. PCC 7942. No additional nitrate assimilation-related genes were identified in about 5 kb sequenced downstream of nrtC. All four genes are arranged as an operon with a promoter-like region upstream of the nirA gene. Transcripts of these nitrate assimilation genes accumulated after long periods of nitrogen starvation. This operon also contains inverted repeat sequences in the intercistronic regions which might be involved in mRNA processing or stability.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco, Bilbao, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Merchán
authors.forename: K L
authors.initials: KL
authors.lastname: Kindle
authors.forename: M J
authors.initials: MJ
authors.lastname: Llama
authors.forename: J L
authors.initials: JL
authors.lastname: Serra
authors.forename: E
authors.initials: E
authors.lastname: Fernández
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics; D009584:Nitrogen / Q000172:deficiency; D009876:Operon / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA
chemical_list: D008565:Membrane Proteins; D009566:Nitrates; D012333:RNA, Messenger; D000255:Adenosine Triphosphate; D009572:Nitrite Reductases; D009584:Nitrogen