Identification of Six Loci in Which Mutations Partially Restore Peroxisome Biogenesis and/or Alleviate the Metabolic Defect of pex2 Mutants in Podospora

Corresponding author: Marguerite Picard, Bat. 400, Université Paris-Sud, 91405 Orsay Cedex, France., picard{at}igmors.u-psud.fr (E-mail)

Communicating editor: M. ZOLAN

Peroxins (PEX) are proteins required for peroxisome biogenesis. Mutations in PEX genes cause lethal diseases in humans, metabolic defects in yeasts, and developmental disfunctions in plants and filamentous fungi. Here we describe the first large-scale screening for suppressors of a pex mutation. In Podospora anserina, pex2 mutants exhibit a metabolic defect [inability to grow on medium containing oleic acid (OA medium) as sole carbon source] and a developmental defect (inability to differentiate asci in homozygous crosses). Sixty-three mutations able to restore growth of pex2 mutants on OA medium have been analyzed. They fall in six loci (suo1 to suo6) and act as dominant, allele-nonspecific suppressors. Most suo mutations have pleiotropic effects in a pex2⁺ background: formation of unripe ascospores (all loci except suo5 and suo6), impaired growth on OA medium (all loci except suo4 and suo6), or sexual defects (suo4). Using immunofluorescence and GFP staining, we show that peroxisome biogenesis is partially restored along with a low level of ascus differentiation in pex2 mutant strains carrying either the suo5 or the suo6 mutations. The data are discussed with respect to ß-oxidation of fatty acids, peroxisome biogenesis, and cell differentiation.

This article has been cited by other articles:

				M. J. Hynes, S. L. Murray, G. S. Khew, and M. A. Davis Genetic Analysis of the Role of Peroxisomes in the Utilization of Acetate and Fatty Acids in Aspergillus nidulans Genetics, March 1, 2008; 178(3): 1355 - 1369. [Abstract] [Full Text] [PDF]

				I. Engh, C. Wurtz, K. Witzel-Schlomp, H. Y. Zhang, B. Hoff, M. Nowrousian, H. Rottensteiner, and U. Kuck The WW Domain Protein PRO40 Is Required for Fungal Fertility and Associates with Woronin Bodies Eukaryot. Cell, May 1, 2007; 6(5): 831 - 843. [Abstract] [Full Text] [PDF]

				M. J. Hynes, S. L. Murray, A. Duncan, G. S. Khew, and M. A. Davis Regulatory Genes Controlling Fatty Acid Catabolism and Peroxisomal Functions in the Filamentous Fungus Aspergillus nidulans Eukaryot. Cell, May 1, 2006; 5(5): 794 - 805. [Abstract] [Full Text] [PDF]