Histone H2B.8 compacts flowering plant sperm through chromatin phase separation.
Nature
; 611(7936): 614-622, 2022 Nov.
Article
in En
| MEDLINE
| ID: mdl-36323776
ABSTRACT
Sperm chromatin is typically transformed by protamines into a compact and transcriptionally inactive state1,2. Sperm cells of flowering plants lack protamines, yet they have small, transcriptionally active nuclei with chromatin condensed through an unknown mechanism3,4. Here we show that a histone variant, H2B.8, mediates sperm chromatin and nuclear condensation in Arabidopsis thaliana. Loss of H2B.8 causes enlarged sperm nuclei with dispersed chromatin, whereas ectopic expression in somatic cells produces smaller nuclei with aggregated chromatin. This result demonstrates that H2B.8 is sufficient for chromatin condensation. H2B.8 aggregates transcriptionally inactive AT-rich chromatin into phase-separated condensates, which facilitates nuclear compaction without reducing transcription. Reciprocal crosses show that mutation of h2b.8 reduces male transmission, which suggests that H2B.8-mediated sperm compaction is important for fertility. Altogether, our results reveal a new mechanism of nuclear compaction through global aggregation of unexpressed chromatin. We propose that H2B.8 is an evolutionary innovation of flowering plants that achieves nuclear condensation compatible with active transcription.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pollen
/
Chromatin
/
Histones
/
Arabidopsis
/
Cell Size
Language:
En
Journal:
Nature
Year:
2022
Document type:
Article
Affiliation country: