Figure 1. Comparison of chromatin features of Fusarium and Neurospora chromosomes with SMCs.

A. Fusarium graminearum Chromosome 2 contains twelve SMCs that can be identified by keystone enzymes (from left to right: STC5, FGSG_08181; PKS23, FGSG_08208; NRPS7, FGSG_08209; PKS7, FGSG_08795; DTC1, FGSG_03066; NRPS11, FGSG_03245; PKS13, FGSG_03340; STC4, FGSG_03494; Tri8, FGSG_03532; NRPS6, FGSG_03747; PKS28, FGSG_03964; PKS29, FGSG_04588; nomenclature for SMCs according to [2]. Except for PKS7, all SMCs are in silent regions enriched with H3K27me3 (orange). None are in regions enriched with H3K4me2 (green), a modification most often found in the promoters of active genes. This suggested that none of these SMCs are expressed in wild type (WT), which was validated by RNA-seq (WT mRNA). In contrast, all SMCs are expressed or overexpressed in an H3K27me3 mutant, kmt6 (kmt6 mRNA), except for STC5 and PKS7 that either require activating factors (STC5) or are not subject to gene silencing by H3K27me3 (PKS7). The thousands of transcripts generated or predicted from Chromosome 2 are indicated, at this resolution as solid bar (transcripts). The centromeric region (Cen2) is indicated by a circle. B. Neurospora crassa Linkage Group (LG) VI has four SMCs (from left to right: NRPS-2, NCU07119; CSY, NCU04801; PKS-1, NCU06013, PKS-2, NCU05011). Of the four clusters, only NRPS-2 is enriched for H3K27me3 (orange). CSY and PKS-1 are enriched in H3K4me2 (green) and expressed at low levels under standard growth conditions (Vogel’s minimal medium at 32C), while PKS-2 is not enriched for any of the tested histone modifications and not expressed under standard laboratory conditions. The pks-1 gene resides near the right edge of Cen VI (CenH3 localization in purple), directly next to a tract of H3K9me3 (red). Histones and their modifications were assayed byCh IP-seq of chromatin precipitated with antibodies against GFP-tagged CenH3, H3K4me2, H3K9me3 and H3K27me3 as described [13].