Methylation-independent Binding to Histone H3 and Cell Cycle-dependent Incorporation of HP1β into Heterochromatin
| Autor: | Prim B. Singh, Dimitra Makatsori, Niki Kourmouli, George Dialynas, Stefan Terjung, Spyros D. Georgatos, Panayiotis A. Theodoropoulos, Kevin McLean |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Chromosomal Proteins
Non-Histone Heterochromatin Molecular Sequence Data Plasma protein binding Methylation Biochemistry Histones Histone H3 Dogs medicine Animals Humans Nucleosome Amino Acid Sequence Molecular Biology Cell Nucleus biology Cell Cycle Cell Biology Molecular biology Rats Cell biology Cell nucleus Histone medicine.anatomical_structure Chromobox Protein Homolog 5 Histone fold biology.protein Heterochromatin protein 1 HeLa Cells Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 281:14350-14360 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m600558200 |
| Popis: | We have examined HP1beta-chromatin interactions in different molecular contexts in vitro and in vivo. Employing purified components we show that HP1beta exhibits selective, stoichiometric, and salt-resistant binding to recombinant histone H3, associating primarily with the helical "histone fold" domain. Furthermore, using "bulk" nucleosomes released by MNase digestion, S-phase extracts, and fragments of peripheral heterochromatin, we demonstrate that HP1beta associates more tightly with destabilized or disrupted nucleosomes (H3/H4 subcomplexes) than with intact particles. Western blotting and mass spectrometry data indicate that HP1beta-selected H3/H4 particles and subparticles possess a complex pattern of posttranslational modifications but are not particularly enriched in me3K9-H3. Consistent with these results, mapping of HP1beta and me3K9-H3 sites in vivo reveals overlapping, yet spatially distinct patterns, while transient transfection assays with synchronized cells show that stable incorporation of HP1beta-gfp into heterochromatin requires passage through the S-phase. The data amassed challenge the dogma that me3K9H3 is necessary and sufficient for HP1 binding and unveil a new mode of HP1-chromatin interactions. |
| Databáze: | OpenAIRE |
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