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Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast
Published on: January 26, 2017
Global replication-independent histone H4 exchange in budding yeast
Jeffrey Linger1, Jessica K Tyler
1UCHSC at Fitzsimons, Mail stop 8101, P.O. Box 6511, Aurora, CO 80045, USA. Jessica.tyler@uchsc.edu
Eukaryotic Cell
|August 29, 2006
Summary
Histones can be incorporated into chromatin in budding yeast regardless of DNA replication or transcription. This chromatin remodeling occurs dynamically throughout the cell cycle, indicating greater genomic plasticity than previously understood.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Eukaryotic genomes are organized into chromatin by packaging DNA with histone proteins.
- Previous research suggested histone assembly into chromatin primarily occurs post-DNA replication.
- Emerging evidence indicated potential histone exchange independent of DNA replication, possibly linked to transcription.
Purpose of the Study:
- To investigate histone H4 incorporation into chromatin in Saccharomyces cerevisiae.
- To determine if histone assembly is dependent on DNA replication or cell cycle phase.
- To examine the role of specific histone chaperones in this process.
Main Methods:
- Utilizing epitope-tagged histone H4 for tracking incorporation in yeast.
- Analyzing histone incorporation across different cell cycle phases (G1-arrested vs. replication).
- Assessing histone incorporation in transcriptionally active, inactive, and silenced genomic regions.
- Investigating the necessity of histone chaperones CAF-1, Asf1, and Hir1.
Main Results:
- Epitope-tagged histone H4 incorporation occurs genome-wide in yeast, irrespective of cell cycle stage.
- Histone incorporation levels in G1-arrested cells are comparable to those during DNA replication.
- Histone H4 assembly is not dependent on the individual action of chaperones CAF-1, Asf1, or Hir1.
- Incorporation is observed across transcriptionally active, silent, and non-transcribed genomic regions.
Conclusions:
- DNA replication is not a prerequisite for histone H4 incorporation into budding yeast chromatin.
- Transcription status does not dictate the rate or location of histone exchange.
- Chromatin exhibits a higher degree of dynamic turnover than previously assumed.
- Histone dynamics contribute to a more flexible genome structure in yeast.
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