The CyAbrB transcription factor Alr0946 regulates the iron superoxide dismutase in Nostoc sp. strain PCC 7120

• In the present investigation we analyse the results of induced over-production of the CyAbrB transcription factor Alr0946 in the cyanobacterium Nostoc sp. PCC 7120 with special focus on its effects on FeSOD. With gel based quantitative proteomics the induced over-expression of Alr0946 was shown to influence the abundance of at least 25 proteins. One of the proteins with a significant lower abundance was FeSOD, one of two types of superoxide dismutases in Nostoc sp. PCC 7120. The change in protein abundance was also followed by lower transcript as well as activity levels. Purified Alr0946 from Nostoc sp. PCC 7120 was shown to interact with the promoter region of alr2938, encoding FeSOD, indicating a transcriptional regulation of FeSOD by Alr0946. The Alr0946 over-expression strain showed a bleaching phenotype with lower growth rate and truncated filaments already two days after induction of over-expression. The phenotype was even more pronounced when illumination was increased from 35 to 125 μmol m-2s-1. This is in line with an increased need of FeSOD during a stronger oxidative stress. The results indicate that Alr0946 is involved in regulation of stress responses and that FeSOD has a specific and important function in the oxidative stress tolerance of the multicellular cyanobacterium Nostoc sp. PCC 7120.

Nyckelord

Nostoc sp. PCC 7120

FeSOD

Alr0946

transcription factor

CyAbrB

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)