Phycomyces MADB interacts with MADA to form the primary photoreceptor complex for fungal phototropism

Sanz, C., Rodriguez-Romero, J., Idnurm, A., Christie, J.M. , Heitman, J., Corrochano, L.M. and Eslava, A.P. (2009) Phycomyces MADB interacts with MADA to form the primary photoreceptor complex for fungal phototropism. Proceedings of the National Academy of Sciences of the United States of America, 106(17), pp. 7095-7100. (doi: 10.1073/pnas.0900879106)

Abstract

The fungus Phycomyces blakesleeanus reacts to environmental signals, including light, gravity, touch, and the presence of nearby objects, by changing the speed and direction of growth of its fruiting body (sporangiophore). Phototropism, growth toward light, shares many features in fungi and plants but the molecular mechanisms remain to be fully elucidated. Phycomyces mutants with altered phototropism were isolated approximate to 40 years ago and found to have mutations in the mad genes. All of the responses to light in Phycomyces require the products of the madA and madB genes. Weshowed that madA encodes a protein similar to the Neurospora blue-light photoreceptor, zinc-finger protein WC-1. We show here that madB encodes a protein similar to the Neurospora zinc-finger protein WC-2. MADA and MADB interact to form a complex in yeast 2-hybrid assays and when coexpressed in E. coli, providing evidence that phototropism and other responses to light are mediated by a photoresponsive transcription factor complex. The Phycomyces genome contains 3 genes similar to wc-1, and 4 genes similar to wc-2, many of which are regulated by light in a madA or madB dependent manner. We did not detect any interactions between additional WC proteins in yeast 2-hybrid assays, which suggest that MADA and MADB form the major photoreceptor complex in Phycomyces. However, the presence of multiple wc genes in Phycomyces may enable perception across a broad range of light intensities, and may provide specialized photoreceptors for distinct photoresponses

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Christie, Professor John
• Authors: Sanz, C., Rodriguez-Romero, J., Idnurm, A., Christie, J.M., Heitman, J., Corrochano, L.M., and Eslava, A.P.
• Subjects: Q Science > QH Natural history > QH301 Biology; Q Science > QK Botany
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• ISSN: 0027-8424
• ISSN (Online): 1091-6490
• Published Online: 20 April 2009