title: A calmodulin inhibitor, W-7 influences the effect of cyclic adenosine 3', 5'-monophosphate signaling on ligninolytic enzyme gene expression in Phanerochaete chrysosporium.
abstract: The capacity of white-rot fungi to degrade wood lignin may be highly applicable to the development of novel bioreactor systems, but the mechanisms underlying this function are not yet fully understood. Lignin peroxidase (LiP) and manganese peroxidase (MnP), which are thought to be very important for the ligninolytic property, demonstrated increased activity in Phanerochaete chrysosporium RP-78 (FGSC #9002, ATCC MYA-4764™) cultures following exposure to 5 mM cyclic adenosine 3', 5'-monophosphate (cAMP) and 500 μM 3'-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase inhibitor. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that transcription of most LiP and MnP isozyme genes was statistically significantly upregulated in the presence of the cAMP and IBMX compared to the untreated condition. However, 100 μM calmodulin (CaM) inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), which had insignificant effects on fungal growth and intracellular cAMP concentration, not only offset the increased activity and transcription induced by the drugs, but also decreased them to below basal levels. Like the isozyme genes, transcription of the CaM gene (cam) was also upregulated by cAMP and IBMX. These results suggest that cAMP signaling functions to increase the transcription of LiP and MnP through the induction of cam transcription.
authors.affiliation: Environmental Science Graduate School, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone City, Shiga, 522-8533, Japan. tirie@ses.usp.ac.jp.
authors.forename: Takaiku
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yao
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Hida
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Honda
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Wataru
authors.initials: W
authors.lastname: Hashigaya
authors.forename: Kazumi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Irie