CFP1 coordinates histone H3 lysine-4 trimethylation and meiotic cell cycle progression in mouse oocytes

Abstract Histone acetylation plays a key role in the regulation of gene expression. Histone hyperacetylation is associated with chromatin opening and gene transcription, while histone hypoacetylation is associated with chromatin condensation and gene silencing. Abnormal histone hypoacetylation mediated by aberrant activity of histone deacetylases (HDACs) has been found to be associated with silencing of tumor suppressor and growth inhibitory genes in malignant cells. HDAC inhibitors (HDACIs) can relieve HDAC-mediated gene silencing and thereby induce normal patterns of cell cycle, differentiation and apoptosis in malignant cells. HDACI OSU 42 is a novel hydroxamate tethered phenylbutyrate derivative that was designed and synthesized at our institution, and exhibited IC50s at submicromolar level, compared with millimolar level for other members of this classes of HDACIs such as valproic acid (VPA). We characterized the activity of this compound in acute myeloid leukemia (AML) cells. It is known that the fusion proteins AML1/ETO and PML / RAR alpha that characterized t(8;21) and t(15;17) AML silence target genes through recruitment of HDACs to their promoter regions. Therefore we utilized AML1/ETO-positive Kasumi-1 and PML/RARA-positive NB4 cells to test the activity of HDACI OSU 42 and used THP-1 cells, characterized by AF9/MLL fusion gene, as a control. We hypothesized that by virtue of the fusion genes, Kasumi-1 and NB4 are more susceptible to HDACI treatment. IC50s for proliferation inhibition in Kasumi-1 cells treated with HDACI OSU42 were 71.8±14.3nM for 24hr and 31.3± 0.4nM for 48hr, significantly lower than VPA (2.0mM for 24hr, 0.9mM for 48hr). The IC50s for NB4 were 237.7±6.5nM for 24hr and 119±6.4nM for 48hr. As a contrast, IC50 for THP-1 was 507.3±68.3nM for 48hr. HDACI OSU42 inhibited 80% of total HDAC activity at 125nM in both Kasumi-1 and NB4; 30nM HDACI OSU42 induced hyperacetylation of histone H3 and H4. Apoptosis analysis showed that nearly 60% more of Kasumi-1 and NB4 underwent apoptosis after treated with 1μM of HDACI OSU42 for 24hr, compared with their untreated control. On the other hand, the same treatment only induced 15% more of THP-1 undergoing apoptosis. Apoptotic effect of HDACI OSU42 was mediated by activation of caspase 9 and caspase 3. Cell cycle analysis demonstrated that treatment of Kasumi-1 and NB4 with 150nM of HDACI OSU 42 inhibited cell cycle progression and arrested 20% to 30% more cells at S phase or G2/M phase, whereas this treatment had not effect on cell cycle progression of THP-1. This was consistent with the up-regulated expression of p21 at both transcription level and protein level. Q-PCR data suggested that Kasumi-1 and NB4 treated with HDACI OSU42 expressed ~10 folds of p21 higher than untreated cells. Chromatin immunoprecipitation assay revealed 10 to 50 folds increase in acetylation level of histone H3 and H4 associated with p21 promoter. Kasumi-1 and NB4 cells also show differentiation ability (increase in CD14 and CD 13 expression by flow cytometry) when treated with 30nM of HDACI OSU42, whereas THP-1 remained undifferentiated. These results support the activity of HDACI OSU42 as a new potent HDACI in AML.

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Excess histone H3 is a Chk1 inhibitor that controls embryonic cell cycle progression

10.1101/2020.06.09.142414 ◽

2020 ◽

Author(s):

Yuki Shindo ◽

Amanda A. Amodeo

Keyword(s):

Cell Cycle ◽

Cell Fate ◽

Cell Cycle Progression ◽

Histone H3 ◽

Embryonic Cell ◽

Cycle Progression ◽

Cell Cycles ◽

Embryonic Cell Cycle

AbstractThe early embryos of many species undergo a switch from rapid, reductive cleavage divisions to slower, cell fate-specific division patterns at the Mid-Blastula Transition (MBT). The maternally loaded histone pool is used to measure the increasing ratio of nuclei to cytoplasm (N/C ratio) to control MBT onset, but the molecular mechanism of how histones regulate the cell cycle has remained elusive. Here, we show that excess histone H3 inhibits the DNA damage checkpoint kinase Chk1 to promote cell cycle progression in the Drosophila embryo. We find that excess H3-tail that cannot be incorporated into chromatin is sufficient to shorten the embryonic cell cycle and reduce the activity of Chk1 in vitro and in vivo. Removal of the Chk1 phosphosite in H3 abolishes its ability to regulate the cell cycle. Mathematical modeling quantitatively supports a mechanism where changes in H3 nuclear concentrations over the final cell cycles leading up to the MBT regulate Chk1-dependent cell cycle slowing. We provide a novel mechanism for Chk1 regulation by H3, which is crucial for proper cell cycle remodeling during early embryogenesis.

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The highly conserved N-terminal domains of histones H3 and H4 are required for normal cell cycle progression

Molecular and Cellular Biology ◽

10.1128/mcb.11.8.4111-4120.1991 ◽

1991 ◽

Vol 11 (8) ◽

pp. 4111-4120

Author(s):

B A Morgan ◽

B A Mittman ◽

M M Smith

Keyword(s):

Cell Cycle ◽

Normal Cell ◽

Cell Cycle Progression ◽

Histone H3 ◽

Temperature Sensitive ◽

Histone H4 ◽

Cycle Progression ◽

Terminal Domain ◽

Normal Cell Cycle ◽

Terminal Domains

The N-terminal domains of the histones H3 and H4 are highly conserved throughout evolution. Mutant alleles deleted for these N-terminal domains were constructed in vitro and examined for function in vivo in Saccharomyces cerevisiae. Cells containing a single deletion allele of either histone H3 or histone H4 were viable. Deletion of the N-terminal domain of histone H4 caused cells to become sterile and temperature sensitive for growth. The normal cell cycle progression of these cells was also altered, as revealed by a major delay in progression through the G2 + M periods. Deletion of the N-terminal domain of histone H3 had only minor effects on mating and the temperature-sensitive growth of mutant cells. However, like the H4 mutant, the H3 mutants had a significant delay in completing the G2 + M periods of the division cycle. Double mutants containing N-terminal domain deletions of both histone H3 and histone H4 were inviable. The phenotypes of cells subject to this synthetic lethality suggest that the N-terminal domains are required for functions essential throughout the cell division cycle and provide genetic evidence that histones are randomly distributed during chromosome replication.

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