No sex in red light - A role for phytochromes in Aspergillus nidulans.

Anne Blumenstein , Kay Vienken , Ronja Tasler , Nicole 1 1 2 Frankenberg-Dinkel and Reinhard Fischer

Author address: 

University of Marburg and University of Karlsruhe, University of Braunschweig.

Abstract: 

Phytochromes are photoreceptors that sense red and far-red light through photo-interconversion between two stable conformations. This distinct feature is mediated by a covalently bound linear tetrapyrrole chromophore. Phytochromes were thought to be confined to photosynthetic organisms including cyanobacteria, but have been recently discovered in heterotrophic bacteria and in fungi, where little is known about their functions . PhsA and orthologues from other fungi share chromophore-binding regions, which are 1 phylogenetically closer related to bacteria than to plants, pointing to their evolution from a common bacterial ancestor. In support of that, all fungal phytochromes are multifunctional proteins, where the phytochrome region and histidine kinase domain are combined in a single protein with a C-terminal response regulator domain.We studied the role of the Aspergillus nidulans phytochrome (PhsA). PhsA expressed in E. coli autoassembled with biliverdin and less efficiently with phycocyanobilin. The functionality of the two-component system histidine kinase was shown in an in vitro kinase assay. We found that A. nidulans PhsA acts as red-light sensor and represses sexual development under red-light conditions. PhsA-GFP was excluded from nuclei, suggesting that red-light perception occurs in the cytoplasm, in contrast to blue-light perception through the nuclear flavoprotein WC-1 in Neurospora crassa . 2,3 1. Bhoo, S.-H., Davis, S. J., Walker, J., Karniol, B. & Vierstra, R. D., Nature 414, 776-779 (2001). 2. Schwerdtfeger, C. & Linden, H., Eur. J. Biochem. 267, 414-421 (2000). 3. Froehlich, A. C., Liu, Y., Loros, J. J. & Dunlap, J. C., Science 297, 815-819 (2002)
2005

abstract No: 

16.

Full conference title: 

23rd Fungal Genetics Conference
    • Fungal Genetics Conference 23rd (2002)