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A nonsense mutation of human XRCC4 is associated with adult-onset progressive encephalocardiomyopathy.

Bee L, Nasca A, Zanolini A, Cendron F, d'Adamo P, Costa R, Lamperti C, Celotti L, Ghezzi D, Zeviani M - EMBO Mol Med (2015)

Bottom Line: XRCC4 transcript levels were profoundly reduced, and the protein was undetectable in patients' skin fibroblasts.Gamma-irradiated mutant cells demonstrated reduction, but not abolition, of DSB repair.Surprisingly, neither immunodeficiency nor predisposition to malignancy was reported in these patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Padua, Padua, Italy.

No MeSH data available.


Related in: MedlinePlus

γ-H2AX nuclear foci formation in different cell cycle phasesA, B Percentages of γ-H2AX nuclear foci remaining in CENP-F-negative (A) and CENP-F-positive (B) cells at the indicated time-points after irradiation with 0.5 Gy of γ-rays. Values, subtracted of their non-irradiated controls, are the mean ± SD of three independent experiments. ***P < 0.001; *P < 0.05 (XRCC4m/m versus XRCC4wt cells), two-way ANOVA, Bonferroni post hoc test.C Immunofluorescence micrographs of γ-H2AX foci in CENP-F-positive and negative fibroblasts at 2 h after irradiation. Arrow heads indicate the CENP-F-positive cells.
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fig03: γ-H2AX nuclear foci formation in different cell cycle phasesA, B Percentages of γ-H2AX nuclear foci remaining in CENP-F-negative (A) and CENP-F-positive (B) cells at the indicated time-points after irradiation with 0.5 Gy of γ-rays. Values, subtracted of their non-irradiated controls, are the mean ± SD of three independent experiments. ***P < 0.001; *P < 0.05 (XRCC4m/m versus XRCC4wt cells), two-way ANOVA, Bonferroni post hoc test.C Immunofluorescence micrographs of γ-H2AX foci in CENP-F-positive and negative fibroblasts at 2 h after irradiation. Arrow heads indicate the CENP-F-positive cells.

Mentions: To analyze the contribution of the two main DSB repair systems, NHEJ and HR, during cell cycle, we distinguished G1, S, and G2/M cells on the basis of their nuclear immunofluorescence intensity to the CENP-F protein, whose expression and localization are cell cycle dependent. CENP-F is detectable by in situ immunofluorescence throughout late S, G2, and M phases of the cell cycle, but it is absent in G1 (Bee et al, 2013). By staining the cells with a CENP-F antibody, we observed that in CENP-F-negative cells (G1-phase), in which DSB rejoining is carried out by NHEJ, DNA repair proceeded significantly slower in XRCC4m/m than in XRCC4wt cells (Fig3A), although at the 24-h endpoint, the differences became non-significant. In CENP-F-positive cells (late S and G2 phase), in which HR system is fully active, DSBs repair was similar at any time-point between wt and XRCC4-mutant cells (Fig3B).


A nonsense mutation of human XRCC4 is associated with adult-onset progressive encephalocardiomyopathy.

Bee L, Nasca A, Zanolini A, Cendron F, d'Adamo P, Costa R, Lamperti C, Celotti L, Ghezzi D, Zeviani M - EMBO Mol Med (2015)

γ-H2AX nuclear foci formation in different cell cycle phasesA, B Percentages of γ-H2AX nuclear foci remaining in CENP-F-negative (A) and CENP-F-positive (B) cells at the indicated time-points after irradiation with 0.5 Gy of γ-rays. Values, subtracted of their non-irradiated controls, are the mean ± SD of three independent experiments. ***P < 0.001; *P < 0.05 (XRCC4m/m versus XRCC4wt cells), two-way ANOVA, Bonferroni post hoc test.C Immunofluorescence micrographs of γ-H2AX foci in CENP-F-positive and negative fibroblasts at 2 h after irradiation. Arrow heads indicate the CENP-F-positive cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4520657&req=5

fig03: γ-H2AX nuclear foci formation in different cell cycle phasesA, B Percentages of γ-H2AX nuclear foci remaining in CENP-F-negative (A) and CENP-F-positive (B) cells at the indicated time-points after irradiation with 0.5 Gy of γ-rays. Values, subtracted of their non-irradiated controls, are the mean ± SD of three independent experiments. ***P < 0.001; *P < 0.05 (XRCC4m/m versus XRCC4wt cells), two-way ANOVA, Bonferroni post hoc test.C Immunofluorescence micrographs of γ-H2AX foci in CENP-F-positive and negative fibroblasts at 2 h after irradiation. Arrow heads indicate the CENP-F-positive cells.
Mentions: To analyze the contribution of the two main DSB repair systems, NHEJ and HR, during cell cycle, we distinguished G1, S, and G2/M cells on the basis of their nuclear immunofluorescence intensity to the CENP-F protein, whose expression and localization are cell cycle dependent. CENP-F is detectable by in situ immunofluorescence throughout late S, G2, and M phases of the cell cycle, but it is absent in G1 (Bee et al, 2013). By staining the cells with a CENP-F antibody, we observed that in CENP-F-negative cells (G1-phase), in which DSB rejoining is carried out by NHEJ, DNA repair proceeded significantly slower in XRCC4m/m than in XRCC4wt cells (Fig3A), although at the 24-h endpoint, the differences became non-significant. In CENP-F-positive cells (late S and G2 phase), in which HR system is fully active, DSBs repair was similar at any time-point between wt and XRCC4-mutant cells (Fig3B).

Bottom Line: XRCC4 transcript levels were profoundly reduced, and the protein was undetectable in patients' skin fibroblasts.Gamma-irradiated mutant cells demonstrated reduction, but not abolition, of DSB repair.Surprisingly, neither immunodeficiency nor predisposition to malignancy was reported in these patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Padua, Padua, Italy.

No MeSH data available.


Related in: MedlinePlus