Elucidation of the Two H3K36me3 Histone Methyltransferases Set2 and Ash1 in Fusarium fujikuroi Unravels Their Different Chromosomal Targets and a Major Impact of Ash1 on Genome Stability

Abstract

In this work, we present a comprehensive analysis of the H3K36 histone methyltransferases Set2 and Ash1 in the filamentous ascomycete In, one single methyltransferase, Set2, confers all H3K36 methylation, while there are two members of the Set2 family in filamentous fungi, and even more H3K36 methyltransferases in higher eukaryotes. Whereas the yeast Set2 homolog has been analyzed in fungi previously, the second member of the Set2 family, designated Ash1, has not been described for any filamentous fungus. Western blot and ChIP-Seq analyses confirmed that Set2 and Ash1 are H3K36-specific histone methyltransferases that deposit H3K36me3 at specific loci: Set2 is most likely responsible for H3K36 methylation of euchromatic regions of the genome, while Ash1 methylates H3K36 at the subtelomeric regions (facultative heterochromatin) of all chromosomes, including the accessory chromosome XII. Our data indicate that H3K36me3 cannot be considered a hallmark of euchromatin in, and likely also other filamentous fungi, making them different to what is known about nuclear characteristics in yeast and higher eukaryotes. We suggest that the H3K36 methylation mark exerts specific functions when deposited at euchromatic or subtelomeric regions by Set2 or Ash1, respectively. We found an enhanced level of H3K27me3, an increased instability of subtelomeric regions and losses of the accessory chromosome XII over time in Δ mutants, indicating an involvement of Ash1 in DNA repair processes. Further phenotypic analyses revealed a role of H3K36 methylation in vegetative growth, sporulation, secondary metabolite biosynthesis, and virulence in .

Set1 and Kdm5 are antagonists for H3K4 methylation and regulators of the major conidiation‐specific transcription factor gene ABA1 in Fusarium fujikuroi

“…C). In contrast, the in loco integration of the point‐mutated variant SET1 H1191K , in which the catalytically active histidine of the SET domain has been mutated to a lysine residue (Tanaka et al ., ; Janevska et al ., ), did not complement as expected (Fig. C).…”

“…The WT, Δ set1 , Δ kdm5 and OE:: KDM5 mutants were grown in liquid ICI medium with 60 mM Gln for 3 days. Western blot detection of K4‐methylated H3 proteins in a whole‐protein extract was done as described elsewhere (Janevska et al ., ). The following primary antibodies were used (Active Motif, La Hulpe, Belgium): anti‐H3K4me1 (#39298; 1:10 000), anti‐H3K4me2 (#39141; 1:10 000), anti‐H3K4me3 (#39159; 1:10 000) and anti‐H3 C‐terminal (#39163; 1:10 000).…”

“…In contrast, methylation of H3K4 and H3K36 is considered as hallmark of euchromatin in yeast and higher eukaryotes (Rando and Chang, ; Wagner and Carpenter, ). However, the picture seems to be more diverse in filamentous fungi, as recent data revealed the ubiquitous presence of the H3K36 trimethylation (me3) mark and accordingly, no correlation with active transcription in both F. fujikuroi and Fusarium graminearum (Connolly et al ., ; Janevska et al ., ).…”

Lysine acetylation contributes to development, aflatoxin biosynthesis and pathogenicity in Aspergillus flavus

“…). Such phenotypic changes are consistent with defective sexual development in methyltransferases knockout mutants in Fusarium fujikuroi (Janevska et al ., ) and Magnaporthe oryzae (Pham et al ., ). In recent years, several studies have shown that acetylation of histones and non‐histones regulates growth and development in various fungi, such as F. graminearum , M. oryzae and C. albicans .…”

G9α‐dependent histone H3K9me3 hypomethylation promotes overexpression of cardiomyogenesis‐related genes in foetal mice

“…However, it is known that HMTs include many subtypes. 27,28 We specifically examined G9α-HMT, which is closely related to cardiac development and expressed in the heart. Western blotting analysis confirmed that the level of G9α was significantly lower in alcohol-treated mice than in control animals and showed that alcohol caused histone H3K9me3 hypomethylation.…”