AI Article Synopsis
- - The study investigates the structure and function of the HIRA/Hir histone chaperone complex in collaboration with ASF1a/Asf1, which are essential for depositing histone tetramers onto DNA for chromatin assembly without replication.
- - Researchers used cryo-electron microscopy (cryo-EM) to reveal the architecture of the S. cerevisiae Hir complex, finding that it forms an arc-shaped dimer with a specific arrangement of its subunits, which helps in positioning histones effectively.
- - The findings indicate that the Hir/Asf1 complex works to enhance histone tetramer formation and their integration into DNA, showcasing a potential mechanism for chromatin assembly.
Article Abstract
The evolutionarily conserved HIRA/Hir histone chaperone complex and ASF1a/Asf1 co-chaperone cooperate to deposit histone (H3/H4) tetramers on DNA for replication-independent chromatin assembly. The molecular architecture of the HIRA/Hir complex and its mode of histone deposition have remained unknown. Here, we report the cryo-EM structure of the S. cerevisiae Hir complex with Asf1/H3/H4 at 2.9-6.8 Å resolution. We find that the Hir complex forms an arc-shaped dimer with a Hir1/Hir2/Hir3/Hpc2 stoichiometry of 2/4/2/4. The core of the complex containing two Hir1/Hir2/Hir2 trimers and N-terminal segments of Hir3 forms a central cavity containing two copies of Hpc2, with one engaged by Asf1/H3/H4, in a suitable position to accommodate a histone (H3/H4) tetramer, while the C-terminal segments of Hir3 harbor nucleic acid binding activity to wrap DNA around the Hpc2-assisted histone tetramer. The structure suggests a model for how the Hir/Asf1 complex promotes the formation of histone tetramers for their subsequent deposition onto DNA.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11338637 | PMC |
| http://dx.doi.org/10.1016/j.molcel.2024.05.031 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!