In:
Epigenetics & Chromatin, Springer Science and Business Media LLC, Vol. 4, No. 1 ( 2011-12)
Abstract:
Histone H1 is an important constituent of chromatin, and is involved in regulation of its structure. During the cell cycle, chromatin becomes locally decondensed in S phase, highly condensed during metaphase, and again decondensed before re-entry into G 1 . This has been connected to increasing phosphorylation of H1 histones through the cell cycle. However, many of these experiments have been performed using cell-synchronization techniques and cell cycle-arresting drugs. In this study, we investigated the H1 subtype composition and phosphorylation pattern in the cell cycle of normal human activated T cells and Jurkat T-lymphoblastoid cells by capillary electrophoresis after sorting of exponentially growing cells into G 1 , S and G 2 /M populations. Results We found that the relative amount of H1.5 protein increased significantly after T-cell activation. Serine phosphorylation of H1 subtypes occurred to a large extent in late G 1 or early S phase in both activated T cells and Jurkat cells. Furthermore, our data confirm that the H1 molecules newly synthesized during S phase achieve a similar phosphorylation pattern to the previous ones. Jurkat cells had more extended H1.5 phosphorylation in G 1 compared with T cells, a difference that can be explained by faster cell growth and/or the presence of enhanced H1 kinase activity in G 1 in Jurkat cells. Conclusion Our data are consistent with a model in which a major part of interphase H1 phosphorylation takes place in G 1 or early S phase. This implies that H1 serine phosphorylation may be coupled to changes in chromatin structure necessary for DNA replication. In addition, the increased H1 phosphorylation of malignant cells in G 1 may be affecting the G 1 /S transition control and enabling facilitated S-phase entry as a result of relaxed chromatin condensation. Furthermore, increased H1.5 expression may be coupled to the proliferative capacity of growth-stimulated T cells.
Type of Medium:
Online Resource
ISSN:
1756-8935
DOI:
10.1186/1756-8935-4-15
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2011
detail.hit.zdb_id:
2462129-8
SSG:
15,3
