%0 Journal Article %A Ghassemian, Majid %A Wong, Bess %A Ferreira, Fernando %A Markley, John L. %A Straus, Neil A. %T Cloning, sequencing and transcriptional studies of the genes for cytochrome c-553 and plastocyanin from Anabaena sp. PCC 7120 %D 1994 %J Microbiology, %V 140 %N 5 %P 1151-1159 %@ 1465-2080 %R https://doi.org/10.1099/13500872-140-5-1151 %K gene regulation %K plastocyanin %K Anabaena sp. PCC 7120 %K algae %K cytochrome c-553 %K cyanobacteria %I Microbiology Society, %X In some cyanobacteria and eukaryotic algae, cytochrome c-553 (c-552) and plastocyanin function as alternative electron carriers between the cytochrome b 6 -f complex and Photosystem I. In these organisms plastocyanin is the electron carrier under copper-replete conditions, and cytochrome c-553 is the electron carrier during copper deprivation. In this paper we report the cloning, sequencing and transcriptional analysis of the genes for cytochrome c-553 and plastocyanin from Anabaena sp. PCC 7120. The gene for cytochrome c-553 encodes a preprotein containing 111 amino acids with a predicted n-terminal transit peptide sequence of 25 amino acids. The gene for plastocyanin encodes a preprotein containing 139 amino acids with a n-terminal transit peptide sequence of 34 amino acids. RNA transcript analyses indicate that the expression of the genes for cytochrome c-553 (petJ) and plastocyanin (petE) are regulated in reciprocal ways in response to copper concentration. In copper-replete conditions, petJ is expressed at very low levels, but is transcribed at high levels under copper deprivation; petE is down-regulated in the absence of copper, but is rapidly up-regulated when copper is added back to the medium. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-140-5-1151