Fuctional analysis of Crr1 (Copper response regulator 1), a global regulator of nurtritional copper homeostasis in C. reinhardtii

• Applicant: Dr. Frederik Sommer
• Subject Area: Plant Physiology
• Term: from 2004 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5446321

Copper can become toxic for cells if it accumulates in high concentrations, but it is an essential micronutrient since it functions as a cofactor for enzymes that catalyze e.g. redoxreactions. Intracellular concentration and distribution of copper has therefore to be fine tuned. Under copper limiting conditions several enzymes are expressed in C. reinhardtii which i) act to increase copper acquisition or ii) are functionally equivalent substitutes for copper containing proteins. This copper deficiency induced expression requires specific copper responsive elements (CuRE) in the promotor region of the induced genes as well as the transcription factor Crr1 (copper response regulator 1), which specifically binds to the CuRE. Crr1 is predicted to have a Zn/DNA-binding domain, homologoues to the recently discovered plant specific SBP-family transcription factors, as well as three ankyrin repeats, generally involved in protein-protein interaction. This project has two goals: First to characterize Crr1 in terms of abundance/localization, binding specificity of different metals to Crr1 and its implication on DNA-binding. Additional transcription factors interacting with the ankyrin domain on Crr1 should be identified. The proposed experiments will elucidate the mechanism of copper induced gene expression on the molecular level. In a second proteomics based approach further implications on Crr1/copper deficiency and target genes for Crr1 should be identified which can complement microarray data.

• DFG Programme: Research Fellowships
• International Connection: USA
• Cooperation Partner: Professorin Dr. Sabeeha Merchant