ATF-1 transcription factor regulates the expression of ccg-1 and cat-1 genes in response to fludioxonil under OS-2 MAP kinase in Neurospora crassa

• Published in: Fungal genetics and biology 2008-12, Vol.45 (12), p.1562-1569
• Main Authors: Yamashita, Kazuhiro, Shiozawa, Azusa, Watanabe, Setsuko, Fukumori, Fumiyasu, Kimura, Makoto, Fujimura, Makoto
• Format: Article
• Language: English
• Subjects: Antifungal Agents - pharmacology; ascospores; ATF-1 gene; biochemical mechanisms; Catalase; catalase-1 gene; Circadian rhythm; clock-controlled-1 gene; conidia; Dioxoles - pharmacology; DNA, Fungal - metabolism; Electrophoretic Mobility Shift Assay; enzyme activity; enzymes; fludioxonil; Fungal Proteins - biosynthesis; fungus physiology; Gene Deletion; Gene Expression Regulation, Fungal; genes; MAP kinase; mitogen-activated protein kinase; molds (fungi); Mutagenesis, Insertional; Neurospora crassa; Neurospora crassa - genetics; Neurospora crassa - physiology; osmotolerance; Phosphotransferases; Promoter Regions, Genetic; Protein Binding; Pyrroles - pharmacology; signal transduction; transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; transcriptional activation; Two-component signal transduction
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1016/j.fgb.2008.09.012

The ATF/CREB family transcriptional factors are regulated by stress-activated MAP kinase in yeast. The disruptants of the atf-1 gene, which encodes an ATF/CREB family transcriptional factor, were isolated and characterized in Neurospora crassa. The characteristic phenotypes in the os-2 MAP kinase strain, such as osmotic sensitivity and fludioxonil resistance, were not observed in the Δ atf-1 strain; however, like the os-2 strain, up-regulation of the catalase gene cat-1 and the clock-controlled gene ccg-1 by treatment with fludioxonil (1 μg/mL) or 4% NaCl was almost completely abolished in the Δ atf-1 strain. A gel shift assay indicated that ATF-1 bound to the cat-1 and ccg-1 promoters probably through the CRE motifs. The enzyme activity of large-subunit catalase CAT-1, the major conidial catalase, was not detected in the Δ atf-1 strain, suggesting that the production of CAT-1 during formation of conidia is largely dependent on ATF-1. Among 11 clock-controlled genes, the expression of ccg-1, ccg-9, ccg-13, and ccg-14 was induced by fludioxonil in an OS-2-dependent manner; however, induction of ccg-13 and ccg-14 was observed in the Δ atf-1 strain, suggesting the existence of another transcription factor regulated by OS-2. The homozygous cross between the Δ atf-1 strains produced perithecia and ascospores; however, their ascospores never germinated. These findings suggest that ATF-1 acts as one of the transcriptional factors downstream of the OS-2 MAP kinase and probably regulates some genes involved in conidiation, circadian rhythm, and ascospore maturation in N. crassa.