The ACF chromatin remodeling complex is essential for Polycomb repression

ABSTRACT: Establishing and maintaining appropriate gene repression is critical for the health and development of multicellular organisms. Histone H3 lysine 27 (H3K27) methylation is a chromatin modification associated with repressed facultative heterochromatin, but the mechanism of repression remains unclear. We used a forward genetic approach to identify novel genes involved in transcriptional silencing of H3K27 methylated chromatin in the filamentous fungus, Neurospora crassa. We found crf4-1Iswi and crf4-2Itc1/Acf1 are required for repression of a subset of H3K27 methylated genes and that their protein products interact to form an ACF-like chromatin remodeling complex. This N. crassa ACF-like complex is promiscuous, yet can target facultative heterochromatin, where it is responsible for pulling the +1 nucleosome in the 5’ direction. H3K27 methylated genes that are up-regulated when crf4-1Iswi or crf4-2Itc1/Acf1 are deleted show a downstream shift of the +1 nucleosome suggesting that proper nucleosome positioning is important for repression of facultative heterochromatin.

ORGANISM(S): Neurospora crassa

PROVIDER: GSE168277 | GEO | 2022/03/08

REPOSITORIES: GEO