Histone Hyperacetylation in Mitosis Prevents Sister Chromatid Separation and Produces Chromosome Segregation Defects

Abstract

Posttranslational modifications of core histones contribute to driving changes in chromatin conformation and compaction. Herein, we investigated the role of histone deacetylation on the mitotic process by inhibiting histone deacetylases shortly before mitosis in human primary fibroblasts. Cells entering mitosis with hyperacetylated histones displayed altered chromatin conformation associated with decreased reactivity to the anti-Ser 10 phospho H3 antibody, increased recruitment of protein phosphatase 1-δ on mitotic chromosomes, and depletion of heterochromatin protein 1 from the centromeric heterochromatin. Inhibition of histone deacetylation before mitosis produced defective chromosome condensation and impaired mitotic progression in living cells, suggesting that improper chromosome condensation may induce mitotic checkpoint activation. In situ hybridization analysis on anaphase cells demonstrated the presence of chromatin bridges, which were caused by persisting cohesion along sister chromatid arms after centromere separation. Thus, the presence of hyperacetylated chromatin during mitosis impairs proper chromosome condensation during the pre-anaphase stages, resulting in poor sister chromatid resolution. Lagging chromosomes consisting of single or paired sisters were also induced by the presence of hyperacetylated histones, indicating that the less constrained centromeric organization associated with heterochromatin protein 1 depletion may promote the attachment of kinetochores to microtubules coming from both poles

Heterochromatin and its Relationship to Cell Senescence and Cancer Therapy

“…62 In contrast, normal primary human cells tolerated HDIs quite well, despite minor chromosome segregation defects and a delay to progression through mitosis, as described by others previously. [63][64][65][66][67] We also found that in normal primary human cells not expressing HP1bDN, treatment with HDIs caused a rapid relocalization of endogenous HP1 proteins to pericentromeric regions, adjacent to chromosome kinetochores. 62 This relocalization was blocked in the cells expressing HP1bDN.…”

Histone deacetylase inhibitors: molecular mechanisms of action

“…Newly replicated chromatin contains acetylated histones. In culture with TSA, histones in newly synthesized chromatin remain acetylated, and this disrupts the structure and function of the centromere and the pericentric heterochromatin, with loss of binding to heterochromatin binding proteins (Taddei et al, 2001;Cimini et al, 2003). Histone acetylation interferes with histone phosphorylation and disrupts the function of mitotic spindle checkpoint proteins, such as BubR1, hBUB1, CENP-F and CENP-E (Dowling et al, 2005;Robbins et al, 2005).…”

“…Histone acetylation interferes with histone phosphorylation and disrupts the function of mitotic spindle checkpoint proteins, such as BubR1, hBUB1, CENP-F and CENP-E (Dowling et al, 2005;Robbins et al, 2005). As a result, the cells show a transient arrest at prometaphase, followed with aberrant mitosis such as missegregation and loss of chromosomes, resulting in cell death by either apoptosis or, mitotic cell death/ catastrophe (Qiu et al, 2000;Cimini et al, 2003;Xu et al, 2005). HDACi-induced a-tubulin acetylation does not affect mitosis, although a-tubulin is a component of mitotic spindle that mediates mitosis.…”

Histone deacetylase inhibitors and genomic instability

“…Short-term treatment with high doses of TSA induces heterogeneity in chromosome condensation in all mitotic stages, associated with a delay in prophase progression and the occurrence of lagging chromosomes and chromatid bridges in anaphase [86]. In a Xenopus oocyte maturation system commonly used to mimic mitosis, TSA treatment impedes chromosome condensation without preventing meiosis progression [87].…”