Sequential phosphorylation of Ser‐10 on histone H3 and ser‐139 on histone H2AX and ATM activation during premature chromosome condensation: Relationship to cell‐cycle phase and apoptosis

Abstract

Background: Histone H1 and H3 phosphorylation associated with chromatin condensation during mitosis has been studied extensively. Less is known on histone modifications that occur during premature chromosome condensation (PCC). The aim of the present study was to reveal the status of histone H3 and H2AX phosphorylation on Ser-10 and Ser-139, respectively, as well as ATM activation through phosphorylation on Ser-1981, during PCC, and relate these events to cell-cycle phase and to initiation of apoptosis. Materials and Methods: To induce PCC, A549 and HL-60 cells were exposed to the phosphatase inhibitor calyculin A (Cal A). Phosphorylation of histone H3 and H2AX as well as ATM activation were detected immunocytochemically concurrent with analysis of cellular DNA content and activation of caspase-3, a marker of apoptosis. The intensity of cellular fluorescence was measured by flow-or laser scanning cytometry. Results: Induction of PCC led to rapid histone H3 phosphorylation, followed by activation of ATM and then H2AX

The dual-specificity phosphatase hYVH1 (DUSP12) is a novel modulator of cellular DNA content

“…29 As the phosphorylation-deficient and phosphomimetic mutants of Ser 335 displayed differential cytoplasm/nuclear steady state levels, it is possible that the phosphorylation event can contribute to hYVH1 loading onto pre-60S prior to nuclear export and hYVH1 release from the mature 60S subunit in the cytoplasm under normal cell culture conditions, ATM may become activated by calyculin A or okadaic acid treatment without the need for DNA damage. 26 This activity is cell cycle-dependent and at a maximum level during G 2 /M 27 and upon nocodazole and taxolinduced mitotic stress. 28 Thus, since both okadaic acid and calyculin A treatment increased hYVH1 phosphorylation and hYVH1 overexpression increased the percentage of cells in G 2 /M, it will be important to examine if Ser 335 phosphorylation occurs in a G 2 /M-specific manner.…”

Constitutive Histone H2AX Phosphorylation and ATM Activation, the Reporters of DNA Damage by Endogenous Oxidants

“…40,43 It should be stressed, however, that mechanisms of CHP and CAA are different in interphase and in mitotic cells. [44][45][46][47][48] While CHP and CAA in interphase cells most likely reflect a response to DNA damage that may involve the presence of DSBs, in mitotic cells these events may be associated with chromatin condensation. For example, the induction of premature chromosomes condensation triggers CHP and CAA even though there is no evidence of DSB formation.…”

“…For example, the induction of premature chromosomes condensation triggers CHP and CAA even though there is no evidence of DSB formation. 48 It has been speculated that the changes in chromatin structure during mitosis associated with the induction of torsional stress on the DNA double helix that make it more sensitive to single-strand nucleases 49 or susceptible to denaturation, 50,51 may be the signal triggering H2AX phosphorylation and ATM activation. 48 Furthermore, in mitotic cells, activated ATM is also localized at centrosomes where its function may be associated with the monitoring of mitotic spindle integrity.…”

“…48 It has been speculated that the changes in chromatin structure during mitosis associated with the induction of torsional stress on the DNA double helix that make it more sensitive to single-strand nucleases 49 or susceptible to denaturation, 50,51 may be the signal triggering H2AX phosphorylation and ATM activation. 48 Furthermore, in mitotic cells, activated ATM is also localized at centrosomes where its function may be associated with the monitoring of mitotic spindle integrity. 46 Phosphorylation of H2AX at mitosis is also a response to telomere shortening and is associated with induction of cell senescence or apoptosis.…”

HIV-1 Vpr induces ATM-dependent cellular signal with enhanced homologous recombination

“…KU55933, a gift from Dr M O'Connor (KuDOS Pharmaceuticals, England), was dissolved in dimethylsulfoxide (DMSO). GFP was analysed with laser scanning cytometer (LSC; Olympus, Tokyo, Japan) (Huang et al, 2006). Cells cultured in cover slide were immersed in 0.2% Triton X-100 in PBS for 10 min.…”