Klähn lab

Klähn lab

Gene expression control of carbon assimilation in cyanobacteria

PD Dr. Stephan Klähn is the head of the group ‘Molecular Biology of Cyanobacteria’ at the Helmholtz Centre for Environmental Research (UFZ) in Leipzig. His research is settled at the interspace of basic and applied research and majorly targets the regulation of metabolic fluxes in cyanobacteria. As associated member of the SCyCode consortium, his laboratory investigates molecular factors that are believed to be key for the control of enzyme activities and/or their abundance in response to a changed C/N ratio. In the frame of the project, a transcription factor regulating the expression of Calvin cycle genes has been characterized in detail in the model strain Synechocystis sp. PCC 6803. Moreover, the small RNA NsiR4 that controls genes at the post-transcriptional level was investigated. In addition to genetic and physiological approaches, omics-technologies provided by different SCyCode partners were used to get detailed insight into their regulatory network, including transcriptomic (Prof. W.R. Hess), proteomic (Prof. B. Maček) as well as metabolic profiling (Prof. Martin Hagemann). The investigations also revealed an uncharacterized gene encoding a small protein of 51 amino acids as part of those networks. In-depth analyses in collaboration with the group of Prof. Karl Forchhammer verified it as interaction partner of the signaling protein PII and as another key player for the control of metabolic flux, in particular into arginine synthesis. Accordingly, we termed it PII-interacting regulator of arginine synthesis (PirA). Besides its role as a proteinogenic amino acid, arginine is a precursor for the cyanobacterial storage compound cyanophycin, which is of potential interest to biotechnology. Therefore, the obtained results will help to provide a scientific basis for targeted metabolic engineering and, hence, the design of photosynthesis-driven biotechnological applications.

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