Ni interferes in the Cu-regulated transcriptional switch petJ/petE in Synechocystis sp. PCC 6803.
Plastocyanin (petE) plays an essential role in photosynthesis as an electron carrier between cytochrome b6f and photosystem I, and in some cyanobacteria it can be replaced by the haem-containing protein, cytochrome c6(petJ). In Synechocystis sp. PCC 6803, transcription of petE and petJ is activated and repressed, respectively, by Cu. Here, we show that Ni can act similarly to Cu in inducing petE and repressing petJ, thus leading to a partial switch between cytochrome c6and plastocyanin. Transcription of these genes is only altered by Ni in Cu-depleted medium, and none of the Ni-dependent transcription factors described in Synechocystis, NrsR and InrS seem to be involved in this regulation. Finally, we show that plastocyanin is essential for growth under conditions of excess Ni.
Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Spain.
Joaquín
http://orcid.org/0000-0003-1553-8295
J
Giner-Lamia
Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Spain.
Luis
http://orcid.org/0000-0002-3510-0621
L
López-Maury
Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Spain. floren@us.es.
Francisco J
FJ
Florencio
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D045365:Cytochromes c6 / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009532:Nickel / Q000378:metabolism*; D010970:Plastocyanin / Q000235:genetics* / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D045365:Cytochromes c6; D009532:Nickel; D010970:Plastocyanin
cyanobacteria; cytochrome c6; metal homeostasis; plastocyanin