| First Author | Dialynas GK | Year | 2006 |
| Journal | J Biol Chem | Volume | 281 |
| Issue | 20 | Pages | 14350-60 |
| PubMed ID | 16547356 | Mgi Jnum | J:159153 |
| Mgi Id | MGI:4441267 | Doi | 10.1074/jbc.M600558200 |
| Citation | Dialynas GK, et al. (2006) Methylation-independent binding to histone H3 and cell cycle-dependent incorporation of HP1beta into heterochromatin. J Biol Chem 281(20):14350-60 |
| abstractText | 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. |
