Comprehensive analysis of dynamics of histone H4 acetylation in mitotic barley cells

Abstract

Nucleosomal histones are covalently modified at specific amino acid residues. In the case of histone H4, four lysines (K5, K8, K12, and K16) are acetylated. In the current studies, we examined the dynamics of histone H4 acetylation at K8 and K12 in mitotic barley cells using a three-dimensional immunofluorescent method. Based on the results and previous studies on the dynamics of K5 and K16 acetylation, we provide a comprehensive view of the dynamics of H4 acetylation. Interphase nuclei exhibit strong acetylation in the centromeric region at K5, K8 and K12. In the case of K12, strong acetylation at nucleolar organizing regions was observed from prophase to anaphase. The dynamics of K12 were closely related to those of K5. On the other hand, K8 exhibited a pattern of almost uniform acetylation from prophase to telophase and strong acetylation in distal regions of chromosomes at both metaphase and anaphase, which is very similar to the dynamics of K16 acetylation. Thus, it appears that there is pair-wise acetylation of K12 and K5 in the nucleolar organizing regions and of K8 and K16 in the gene-rich regions. Together, these results suggest that pair-wise dynamics of H4 acetylation regulate chromosomal structure and function during the cell cycle.

Site-Specific Identification of Lysine Acetylation Stoichiometries in Mammalian Cells

“…The similarity of the stoichiometry fold changes upon NaBu treatment among closely positioned acetylation sites suggests potential coregulation of these sites through common enzymatic pathways that were induced by the treatment. Our data surprisingly agrees with previous studies on histone acetylation dynamics during cell cycle and during development, suggesting potential coregulation between K5 and K12 and between K8 and K16 acetylation sites at the histone H4 N-terminal. , In addition, newly synthesized histones were known to be primarily diacetylated first at K5 and K12 prior to deposition and acetylated at K8 and K16 after deposition in Tetrahymenas, Drosophila, and human cells. − Genome-wide ChIP-seq data also showed extensive coacetylation of H4K5 and H4K12 . These data further corroborate the notion that specific closely positioned histone acetylation sites are likely to be coregulated by certain mechanisms during cellular processes.…”

Trichostatin A and 5-azacytidine both cause an increase in global histone H4 acetylation and a decrease in global DNA and H3K9 methylation during mitosis in maize

“…Mitosis is a unique cell cycle phase in which duplicated chromosomes are highly condensed. During mitosis, dynamic changes in histone H4 acetylation accompanied by chromatin condensation/decondensation have been reported in mammalian, tobacco and barley cells [ 8 , 10 , 16 , 17 ]. In maize root tips, histone H4 deacetylation and reestablishing was also observed during mitosis.…”

“…In plants, the most intense H4 acetylation occurs during replication in both euchromatin and heterochromatin [ 13 - 15 ]. The deacetylation of H4 during the interphase to metaphase transition has been observed to be associated with chromatin condensation in tobacco protoplasts [ 10 ] as well as in barley [ 16 , 17 ]. In tobacco protoplasts, histone H3 dimethylation at lysine 9 (H3K9me2) and histone H3 dimethylation at lysine 4 (H3K4me2) levels remain unchanged during interphase and mitosis [ 10 ].…”

Higher Organization and Histone Modification of the Plant Nucleus and Chromosome

“…Barley chromosomes carry large amounts of centromeric heterochromatin [Fukui and Kakeda, 1990]; thus clustering of centromeres results in accumulation of centromeric heterochromatin in the limited nuclear subregion, called the centrosphere [Wako et al, 2002]. The clustered centromeres were specifically acetylated at H4K5, K8, and K12 in barley mitotic cells in interphase, and the specific acetylation could be related to formation of the Rabl orientation [Wako et al, 2002[Wako et al, , 2003[Wako et al, , 2005. All barley chromosomes are classified as either metacentric or submetacentric [Fukui and Kakeda, 1990].…”