Absence of p53-dependent cell cycle regulation in pluripotent mouse cell lines

Schmidt-Kastner, Prabha Kulkarni; Jardine, Karen; Cormier, Michelle; McBurney, Michael W.

doi:10.1038/sj.onc.1201835

Cited by 47 publications

(15 citation statements)

References 29 publications

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“…Our evidence for p53-independent developmental arrest in borealin À/À p53 À/À embryos is consistent with previous work which describes p53-independent cell cycle arrest and apoptosis in mouse embryonic stem cells (Prost et al, 1998;Aladjem et al, 1998;Schmidt-Kastner et al, 1998). Our work suggests that similar p53-independent mechanisms may exist in embryonic tissues.…”

Section: Discussionsupporting

confidence: 93%

Loss of Borealin/DasraB leads to defective cell proliferation, p53 accumulation and early embryonic lethality

Yamanaka

Heike

Kumada

et al. 2008

Mechanisms of Development

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Borealin/DasraB is a member of the chromosomal passenger protein complex (CPC) required for proper segregation of chromosomes during mitosis. In Drosophila melanogaster, inactivation of Borealin/DasraB results in polyploidy, delayed mitosis and abnormal tissue development, indicating its critical role for cell proliferation. However, the in vivo role of mammalian Borealin/DasraB remains unclear. Here, we analyzed the expression of Borealin/DasraB and found that borealin is widely expressed in embryonic tissues and later restricted to adult tissues which relies on rapid cell proliferation. To determine the role of borealin during mouse development, we generated borealin-null mice through targeted disruption. While heterozygous mice developed normally, disruption of both borealin alleles resulted in early embryonic lethality by 5.5 dpc (days postcoitus) due to mitotic defects and apoptosis in blastocyst cells that showed microtubule disorganization and no CPC enrichment. At 5.5 dpc, borealin-null embryos exhibited excessive apoptosis and elevated expression of p53. However, loss of p53 did not abrogate or delay embryonic lethality, revealing that Borealin/DasraB inactivation triggered impaired mitosis and apoptosis though p53-independent mechanisms. Our data show that Borealin/DasraB is essential for cell proliferation during early embryonic development, and its early embryonic lethality cannot be rescued by the loss of p53.

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Section: Discussionsupporting

confidence: 93%

Loss of Borealin/DasraB leads to defective cell proliferation, p53 accumulation and early embryonic lethality

Yamanaka

Heike

Kumada

et al. 2008

Mechanisms of Development

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“…Similar to wild-type ES cells (36,37), H2AX ⌬/⌬ ES cells, as well as XRCC4 Ϫ/Ϫ ES cells, arrest at G 2 on exposure to 1,000 rad of IR (Fig. 4, which is published as supporting information on the PNAS web site, www.pnas.org).…”

Section: H2ax-deficient Cells (mentioning

confidence: 99%

Increased ionizing radiation sensitivity and genomic instability in the absence of histone H2AX

Bassing

Chua

Sekiguchi

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

494

420

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In mammalian cells, DNA double-strand breaks (DSBs) cause rapid phosphorylation of the H2AX core histone variant (to form ␥-H2AX) in megabase chromatin domains flanking sites of DNA damage. To investigate the role of H2AX in mammalian cells, we generated H2AX-deficient (H2AX ⌬/⌬ ) mouse embryonic stem (ES) cells. H2AX ⌬/⌬ ES cells are viable. However, they are highly sensitive to ionizing radiation (IR) and exhibit elevated levels of spontaneous and IR-induced genomic instability. Notably, H2AX is not required for NHEJ per se because H2AX ⌬/⌬ ES cells support normal levels and fidelity of V(D)J recombination in transient assays and also support lymphocyte development in vivo. However, H2AX ⌬/⌬ ES cells exhibit altered IR-induced BRCA1 focus formation. Our findings indicate that H2AX function is essential for mammalian DNA repair and genomic stability. The DNA in eukaryotic cells is packaged into chromatin, the fundamental unit of which is the nucleosome. The nucleosome consists of DNA wrapped around an octamer of the four core histones-H2A, H2B, H3, and H4 (1). The H2A histones consist of several subfamilies that contain distinct, conserved amino-and carboxyl-terminal amino acid sequences (2). The H2AX subfamily contains a conserved carboxyl-terminal SerGln-Glu (SQE motif) amino acid sequence. This SQE motif represents the consensus in vitro phosphorylation site for members of the phosphoinositide 3-kinase related kinase (PIKK) family that includes the protein kinases DNA-dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutated (ATM), and ATM and Rad3-related (ATR) (3).The repair of spontaneous and induced DNA double-strand breaks (DSBs) is critical for the maintenance of genomic integrity. In eukaryotic cells, the two major pathways of DSB repair are nonhomologous end-joining (NHEJ) and homologous recombination (HR; refs. 4 and 5). Covalent modifications of core histones via phosphorylation, acetylation, and methylation have been proposed to form a ''histone code'' that is read by cellular proteins to facilitate downstream molecular events (6). In response to DNA damage by agents that induce DNA doublestrand breaks, Mec1, the Saccharomyces cerevisiae homologue of ATR, phosphorylates the SQE motif of H2A (7). This phosphorylation event is required for the efficient repair of chromosomal DSBs by NHEJ but does not appear to be as important for homologous recombination (7). In mammalian cells, H2AX is rapidly phosphorylated on the induction of DSBs by ionizing radiation (IR) and DNA damaging agents (8, 9), resulting in formation of ␥-H2AX foci along megabase chromatin domains flanking DNA damage sites (9).Foci of ␥-H2AX also form at the immunoglobulin heavy chain locus during class switch recombination (CSR) in activated mature B cells (10). CSR occurs between large, highly repetitive S regions and also may be initiated by DSBs (10, 11) and completed by NHEJ factors (12)(13)(14)(15). Notably, CSR is significantly impaired in the absence of H2AX (10). Earlier during lymphocyte development...

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“…p53 is known to transactivate p21, which inhibits cyclin D-CDK4/6 complexes to arrest the cells at the G 1 /S border (31). It was reported that embryonal stem cells and embryonal carcinoma cells lack the G 1 /S checkpoint even though p53 is highly activated after X-irradiation (37,40). In a recent study on ␥-irradiated F9 embryonal carcinoma cells, p53 was shown to activate transcription of the p21 gene, but a rapid degradation blocked accumulation of p21 protein, leading to elimination of the G 1 /S checkpoint (29).…”

Section: Vol 22 2002 P53-dependent S-phase Checkpoint In Mouse Zygomentioning

confidence: 99%

p53-Dependent S-Phase Damage Checkpoint and Pronuclear Cross Talk in Mouse Zygotes with X-Irradiated Sperm

Shimura

Inoue

Taga³

et al. 2002

Molecular and Cellular Biology

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One difficulty in analyzing the damage response is that the effect of damage itself and that of cellular response are hard to distinguish in irradiated cells. In mouse zygotes, damage can be introduced by irradiated sperm, while damage response can be studied in the unirradiated maternal pronucleus. We have analyzed the p53-dependent damage responses in irradiated-sperm mouse zygotes and found that a p53-responsive reporter was efficiently activated in the female pronucleus. [ 3 H]thymidine labeling experiments indicated that irradiated-sperm zygotes were devoid of G 1 /S arrest, but pronuclear DNA synthesis was suppressed equally in male and female pronuclei. p53 ؊/؊ zygotes lacked this suppression, which was corrected by microinjection of glutathione S-transferase-p53 fusion protein. In contrast, p21؊/؊ zygotes exhibited the same level of suppression upon fertilization by irradiated sperm. About a half of the 6-Gy-irradiated-sperm zygotes managed to synthesize a full DNA content by prolonging S phase, while the other half failed to do so. Regardless of the DNA content, all the zygotes cleaved to become two-cell-stage embryos. These results revealed the presence of p53-dependent pronuclear cross talk and a novel function of p53 in the S-phase DNA damage checkpoint of mouse zygotes.

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Absence of p53-dependent cell cycle regulation in pluripotent mouse cell lines

Cited by 47 publications

References 29 publications

Loss of Borealin/DasraB leads to defective cell proliferation, p53 accumulation and early embryonic lethality

Loss of Borealin/DasraB leads to defective cell proliferation, p53 accumulation and early embryonic lethality

Increased ionizing radiation sensitivity and genomic instability in the absence of histone H2AX

p53-Dependent S-Phase Damage Checkpoint and Pronuclear Cross Talk in Mouse Zygotes with X-Irradiated Sperm

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