@article{19602,
  abstract     = {N4-methylcytosine (4mC) is an important DNA modification in prokaryotes, but its relevance and even its presence in eukaryotes have been mysterious. Here we show that spermatogenesis in the liverwort Marchantia polymorpha involves two waves of extensive DNA methylation reprogramming. First, 5-methylcytosine (5mC) expands from transposons to the entire genome. Notably, the second wave installs 4mC throughout genic regions, covering over 50% of CG sites in sperm. 4mC requires a methyltransferase (MpDN4MT1a) that is specifically expressed during late spermiogenesis. Deletion of MpDN4MT1a alters the sperm transcriptome, causes sperm swimming and fertility defects, and impairs post-fertilization development. Our results reveal extensive 4mC in a eukaryote, identify a family of eukaryotic methyltransferases, and elucidate the biological functions of 4mC in reproductive development, thereby expanding the repertoire of functional eukaryotic DNA modifications.},
  author       = {Walker, James and Zhang, Jingyi and Liu, Yalin and Xu, Shujuan and Yu, Yiming and Vickers, Martin and Ouyang, Weizhi and Tálas, Judit and Dolan, Liam and Nakajima, Keiji and Feng, Xiaoqi},
  issn         = {1097-4172},
  journal      = {Cell},
  number       = {11},
  pages        = {2890--2906.e14},
  publisher    = {Elsevier},
  title        = {{Extensive N4 cytosine methylation is essential for Marchantia sperm function}},
  doi          = {10.1016/j.cell.2025.03.014},
  volume       = {188},
  year         = {2025},
}

@article{15375,
  abstract     = {In the eukaryotic nucleus, heterochromatin forms highly condensed, visible foci known as heterochromatin foci (HF). These HF are enriched with linker histone H1, a key player in heterochromatin condensation and silencing. However, it is unknown how H1 aggregates HF and condenses heterochromatin. In this study, we established that H1 facilitates heterochromatin condensation by enhancing inter- and intrachromosomal interactions between and within heterochromatic regions of the Arabidopsis (Arabidopsis thaliana) genome. We demonstrated that H1 drives HF formation via phase separation, which requires its C-terminal intrinsically disordered region (C-IDR). A truncated H1 lacking the C-IDR fails to form foci or recover HF in the h1 mutant background, whereas C-IDR with a short stretch of the globular domain (18 out of 71 amino acids) is sufficient to rescue both defects. In addition, C-IDR is essential for H1's roles in regulating nucleosome repeat length and DNA methylation in Arabidopsis, indicating that phase separation capability is required for chromatin functions of H1. Our data suggest that bacterial H1-like proteins, which have been shown to condense DNA, are intrinsically disordered and capable of mediating phase separation. Therefore, we propose that phase separation mediated by H1 or H1-like proteins may represent an ancient mechanism for condensing chromatin and DNA.},
  author       = {He, Shengbo and Yu, Yiming and Wang, Liang and Zhang, Jingyi and Bai, Zhengyong and Li, Guohong and Li, Pilong and Feng, Xiaoqi},
  issn         = {1532-298X},
  journal      = {The Plant Cell},
  number       = {5},
  pages        = {1829--1843},
  publisher    = {Oxford University Press},
  title        = {{Linker histone H1 drives heterochromatin condensation via phase separation in Arabidopsis}},
  doi          = {10.1093/plcell/koae034},
  volume       = {36},
  year         = {2024},
}