The Indispensable Role of Histone Methyltransferase PoDot1 in Extracellular Glycoside Hydrolase Biosynthesis of Penicillium oxalicum

Abstract

Histone methylation is associated with transcription regulation, but its role for glycoside hydrolase (GH) biosynthesis is still poorly understood. We identified the histone H3 lysine 79 (H3K79)-specific methyltransferase PoDot1 in Penicillium oxalicum. PoDot1 affects conidiation by regulating the transcription of key regulators (BrlA, FlbC, and StuA) of asexual development and is required in normal hyphae septum and branch formation by regulating the transcription of five septin-encoding genes, namely, aspA, aspB, aspC, aspD, and aspE. Tandem affinity purification/mass spectrometry showed that PoDot1 has no direct interaction with transcription machinery, but it affects the expressions of extracellular GH genes extensively. The expression of genes (amy15A, amy13A, cel7A/cbh1, cel61A, chi18A, cel3A/bgl1, xyn10A, cel7B/eg1, cel5B/eg2, and cel6A/cbh2) that encode the top 10 GHs was remarkably downregulated by Podot1 deletion (ΔPodot1). Consistent with the decrease in gene transcription level, the activities of amylases and cellulases were significantly decreased in ΔPodot1 mutants in agar (solid) and fermentation (liquid) media. The repression of GH gene expressions caused by PoDot1 deletion was not mediated by key transcription factors, such as AmyR, ClrB, CreA, and XlnR, but was accompanied by defects in global demethylated H3K79 (H3K79me2) and trimethylated H3K79 (H3K79me3). The impairment of H3K79me2 on specific GH gene loci was observed due to PoDot1 deletion. The results implies that defects of H3K79 methylation is the key reason of the downregulated transcription level of GH-encoding genes and reveals the indispensable role of PoDot1 in extracellular GH biosynthesis.

Quantitative Proteome Profiling Reveals Cellobiose-Dependent Protein Processing and Export Pathways for the Lignocellulolytic Response in Neurospora crassa

“…In N. crassa, CRE-1 is negatively regulated by the transcription factors VIB1 and COL26 (23). Recent studies suggest that the expression of cellulase genes is also regulated by the chromatin status, such as histone methylation (24,25).…”

Carbon catabolite repression involves physical interaction of the transcription factor CRE1/CreA and the Tup1–Cyc8 complex in Penicillium oxalicum and Trichoderma reesei

“…The initial hypothesis is that histone modification and chromatin structure change are the main mechanisms of the gene expression-inhibiting function of the complex [ 38 ]. Histone methylation, specifically on histone H3, regulates cellulolytic gene expression [ 39 – 42 ]. Even the expression of CRE1 itself is related to H3K4 methylation [ 43 ].…”

A Homeodomain-Containing Transcriptional Factor PoHtf1 Regulated the Development and Cellulase Expression in Penicillium oxalicum

“…In P. oxalicum 114-2, three key transcriptional regulators of asexual development have been identified, BrlA, FlbC, and StuA. These proteins regulate the expression levels of pigmentation-related and spore wall protein-related genes ( Qin et al, 2013 ; Yao et al, 2016 ; Li et al, 2019 ). Transcription levels of brlA , flbC , and stuA were analyzed in all strains by RT-PCR.…”

“…The Po Htf1 homeodomain sequence is highly conserved with that of HbxA in A. nidulans ( Figure 1B ), suggesting that Po Htf1 and HbxA have identical conidiation regulation mechanisms. There are three key transcriptional regulators of asexual development, BrlA, FlbC, and StuA, which are involved in conidiation and conidium morphology in P. oxalicum 114-2 ( Qin et al, 2013 ; Yao et al, 2016 ; Li et al, 2019 ). BrlA is the key regulator of conidiation, and deletion of brlA completely blocks conidiation.…”