RT Journal Article SR Electronic T1 Histone H1 limits DNA methylation in Neurospora crassa JF bioRxiv FD Cold Spring Harbor Laboratory SP 041285 DO 10.1101/041285 A1 Michael Seymour A1 Lexiang Ji A1 Alex M. Santos A1 Masayuki Kamei A1 Takahiko Sasaki A1 Evelina Y. Basenko A1 Robert J. Schmitz A1 Xiaoyu Zhang A1 Zachary A. Lewis YR 2016 UL http://biorxiv.org/content/early/2016/02/25/041285.abstract AB Histone H1 variants, known as linker histones, are essential chromatin components in higher eukaryotes, yet compared to the core histones relatively little is known about their in vivo functions. The filamentous fungus Neurospora crassa encodes a single H1 protein that is not essential for viability. To investigate the role of N. crassa H1, we constructed a functional FLAG-tagged H1 fusion protein and performed genomic and molecular analyses. Cell fractionation experiments showed that H1-FLAG is a chromatin binding protein. Chromatin-immunoprecipitation combined with sequencing (ChIP-seq) revealed that H1-3XFLAG is globally enriched throughout the genome with a subtle preference for promoters of expressed genes. In mammals, the stochiometery of H1 impacts nucleosome repeat length. To determine if H1 impacts nucleosome occupancy or nucleosome positioning in N. crassa, we performed Micrococcal nuclease digestion in wildtype and the ΔhH1 strain followed by sequencing (MNase-seq). Deletion of hH1 did not significantly impact nucleosome positioning or nucleosome occupancy. Analysis of DNA methylation by whole-genome bisulfite sequencing (MethylC-seq) revealed a modest but global increase in DNA methylation in the ΔhH1 mutant. Together, these data suggest that H1 acts as a non-specific chromatin binding protein that can limit accessibility of the DNA methylation machinery in N. crassa.