FlbC is a putative nuclear C2H2 transcription factor regulating development in Aspergillus nidulans

• Published in: Molecular microbiology 2010-09, Vol.77 (5), p.1203-1219
• Main Authors: Kwon, Nak‐Jung, Garzia, Aitor, Espeso, Eduardo A., Ugalde, Unai, Yu, Jae‐Hyuk
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Ascomycetes; Aspergillus nidulans; Aspergillus nidulans - genetics; Aspergillus nidulans - growth & development; Aspergillus nidulans - metabolism; Biological and medical sciences; Cell Nucleus - chemistry; Conserved Sequence; DNA, Fungal - genetics; DNA, Fungal - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Deletion; Gene Expression Profiling; Hyphae - growth & development; Microbiology; Miscellaneous; Molecular Sequence Data; Mycology; Promoter Regions, Genetic; Protein Binding; RNA, Messenger - biosynthesis; RNA, Messenger - genetics; Sequence Alignment; Spores, Fungal - growth & development; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2010.07282.x

Summary Asexual development (conidiation) in Aspergillus is governed by multiple regulators. Here, we characterize the upstream developmental activator FlbC in Aspergillus nidulans. flbC mRNA is detectable throughout the life cycle, at relatively high levels during vegetative growth, early asexual and late sexual developmental phases. The deletion of flbC causes a delay/reduction in conidiation, brlA and vosA expression, and conidial germination. While overexpression of flbC (OEflbC) does not elaborate conidiophores, it inhibits hyphal growth and activates expression of brlA, abaA and vosA, but not wetA. FlbC is conserved in filamentous Ascomycetes containing two C2H2 zinc fingers at the C‐terminus and a putative activation domain at the N‐terminus. FlbC localizes in the nuclei of both hyphae and developmental cells. Localization and expression of FlbC are not affected by the absence of FlbB or FlbE, and vice versa. Importantly, overexpression of flbC causes growth inhibition and activation of abaA and vosA in the absence of brlA and abaA respectively. In vitro DNA‐binding assay reveals that FlbC binds to the brlA, abaA and vosA, but not the wetA, promoters. In summary, FlbC is a putative nuclear transcription factor necessary for proper activation of conidiation, and its balanced activity is crucial for governing growth and development in A. nidulans.