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International Union of Microbiological Societies (IUMS, Mycology Division)
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The formation of atroviridin by Hypocrea atroviridis is conidiation-associated, and positively regulated by blue light and the G-protein GNA3

Komon-Zelzowska, M., Neuhof, T., Dieckmann, R., Döhren, H., Herrera-Estrella, A., Kubicek, C. P. and I. S. Druzhinina, 2007
Eukaryotic Cell
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Species of the mycoparasitic fungal genus Hypocrea/Trichodermaare prominent producers of peptaibols, a class of small linearpeptides of fungal origin. Some of these peptaibols have beenshown to act synergistically with cell-wall-degrading enzymesin the inhibition of the growth of other fungi in vitro andin vivo. Here we present the structure of the Hypocrea atroviridispeptaibol synthetase gene (pbs1), deduced from the genome sequenceof H. atroviridis. It consists of 19 typical peptide synthetasemodules with the required additional modifying domains at theN and C termini. Phylogenetic and similarity analyses of theindividual amino acid-activating modules is consistent withits ability to synthesize atroviridins. Matrix-assisted laserdesorption ionization-time of flight mass spectrometry of surface-growncultures of H. atroviridis showed that no peptaibols were formedduring vegetative growth, but a microheterogenous mixture ofatroviridins accumulated when the colonies started to sporulate.This correlation between sporulation and atroviridin formationwas shown to be independent of the pathway inducing sporulation(i.e., light, mechanical injury and carbon starvation, respectively).Atroviridin formation was dependent on the function of the twoblue light regulators, BLR1 and BLR2, under some but not allconditions of sporulation and was repressed in a pkr1 (regulatorysubunit of protein kinase A) antisense strain with constitutivelyactive protein kinase A. Conversely, however, loss of functionof the G{alpha}-protein GNA3, which is a negative regulator of sporulationand leads to a hypersporulating phenotype, fully impairs atroviridinformation. Our data show that formation of atroviridin by H.atroviridis occurs in a sporulation-associated manner but isuncoupled from it at the stage of GNA3

Copyright: Irina Druzhinina & Alexey Kopchinskiy 2004 - 2008