title: Velvet-mediated repression of β-glucan synthesis in Aspergillus nidulans spores.
abstract: Beta-glucans are a heterologous group of fibrous glucose polymers that are a major constituent of cell walls in Ascomycetes and Basidiomycetes fungi. Synthesis of β (1,3)- and (1,6)-glucans is coordinated with fungal cell growth and development, thus, is under tight genetic regulation. Here, we report that β-glucan synthesis in both asexual and sexual spores is turned off by the NF-kB like fungal regulators VosA and VelB in Aspergillus nidulans. Our genetic and genomic analyses have revealed that both VosA and VelB are necessary for proper down-regulation of cell wall biosynthetic genes including those associated with β-glucan synthesis in both types of spores. The deletion of vosA or velB results in elevated accumulation of β-glucan in asexual spores. Double mutant analyses indicate that VosA and VelB play an inter-dependent role in repressing β-glucan synthesis in asexual spores. In vivo chromatin immuno-precipitation analysis shows that both VelB and VosA bind to the promoter region of the β-glucan synthase gene fksA in asexual spores. Similarly, VosA is required for proper repression of β-glucan synthesis in sexual spores. In summary, the VosA-VelB hetero-complex is a key regulatory unit tightly controlling proper levels of β-glucan synthesis in asexual and sexual spores.
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
authors.forename: Hee-Soo
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Yeong
authors.initials: Y
authors.lastname: Man Yu
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
authors.forename: Mi-Kyung
authors.initials: MK
authors.lastname: Lee
authors.affiliation: Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Pil
authors.initials: P
authors.lastname: Jae Maeng
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Dae-Jon, Republic of Korea.
authors.forename: Sun
authors.initials: S
authors.lastname: Chang Kim
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Yu
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D011401:Promoter Regions, Genetic / Q000235:genetics; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism*; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D047071:beta-Glucans