Cap analysis gene expression (CAGE) of Aspergillus luchuensis mut. kawachii control and laeA disruptant strains

LaeA, a putative methyltransferase, is a global regulator for metabolic and development process in filamentous fungi. We characterized the laeA homologous genes in the white koji fungus, Aspergillus luchuensis mut. kawachii (A. kawachii) to examine their role in citric acid production. The ΔlaeA strain showed a significant reduction in the citric acid productivity. The cap-analysis gene expression (CAGE) revealed the laeA is required for the gene expression of a putative citrate exporter encoding cexA, which has a critical role for the citric acid production. The deficient citric acid productivity of the ΔlaeA strain was remedied by overexpression of cexA to a comparative level to that of the cexA overexpressing ΔcexA strain. In addition, chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) analysis indicated that LaeA regulates gene expression of the citrate exporter encoding cexA gene via histone H3K4 and histone H3K9 methylation levels. These results indicate that LaeA is involved in the citric acid production through epigenetic regulation of cexA in A. kawachii. CAGE profiles of Aspergillus luchuensis mut. kawachii control and laeA disruptant strains were investigated by Illumina NextSeq 500.