Expression of the glutamyl-tRNA synthetase gene from the cyanobacterium Synechococcus sp PCC 7942 depends on nitrogen availability and the global regulator NtcA.
We report here transcriptional analyses of a cyanobacterial gene encoding an aminoacyl-tRNA synthetase (aaRS), the gltX gene from Synechoccocus sp. PCC 7942, coding for the glutamyl-tRNA synthetase. We show that the transcript levels of gltX in Synechococcus depend on nitrogen availability and do not increase with the growth rate, which is at odds with observations from other bacteria. We also demonstrate the involvement of the cyanobacterial global regulator NtcA in transcriptional control of gltX according to nitrogen status. Our results support a regulatory model in which the gltX transcript level is finely tuned by a dynamic equilibrium between activation and repression relying upon the cellular concentration of NtcA.
Luque
Ignacio
I
Unité Mixte de Recherche, Centre National de la Recherche Scientifique, Paris, Cedex, France. ignacio.luque@ua.es
Contreras
Asunción
A
Zabulon
Gérald
G
Herrero
Antonia
A
Houmard
Jean
J
D001426:Bacterial Proteins; D001483:Base Sequence; D001665:Binding Sites; D001682:Biological Availability; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005975:Glutamate-tRNA Ligase / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; C075617:ntcA protein, Synechococcus; D005975:Glutamate-tRNA Ligase; D009584:Nitrogen