Neuronal Enhancers are Hotspots for DNA Single-Strand Break Repair [HiC]
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE167255 | GEO | 2021/03/25
REPOSITORIES: GEO
Similar Datasets
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167254 | GEO
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167252 | GEO
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167258 | GEO
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167257 | GEO
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167256 | GEO
Project description:Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here, we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breakage at specific sites within the genome. Genome-wide mapping reveals that these single-strand breaks (SSBs) are located within enhancers at or near to CpG dinucleotides and sites of DNA demethylation, and are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair elevate the extent of DNA repair synthesis at neuronal enhancers, whereas deficiencies in long-patch repair reduce synthesis, suggesting that the high steady-state level of SSB repair in neuronal enhancers is sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell type-specific SSB repair, revealing unexpected levels of localized and continuous DNA single-strand breakage in neurons. In addition, these data suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.
2021-03-25 | GSE167253 | GEO
Project description:Neurons harbor high levels of endogenous single strand DNA breaks (SSBs) that are targeted to neuronal enhancers and correlate with marks of DNA demethylation. To determine the source of SSBs at neuronal enhancers, we depleted the thymidine DNA glycosylase TDG, which excises TET-mediated oxidized methylcytidines 5fC and 5caC, to produce unmodified C. In differentiating neurons, induced degradation of TDG led to the disappearance of SSBs, demonstrating the existence of ongoing TET‑mediated oxidation. Using an independent model of macrophage differentiation from reprogrammed pre-B cells, we demonstrate that TET/TDG-mediated active demethylation may be a general mechanism underlying post-mitotic lineage specification. We find that macrophage differentiation prefers short patch base excision repair (SP-BER) to fill-in single nucleotide gaps, whereas neurons also frequently utilize the long-patch (LP-BER) sub-pathway. By measuring the distribution of SSBs relative to sites of oxidized cytosine, we observed that stretches of 2-30 bases are synthesized distal from the methylated CpG site during repair. Disrupting gap-filling using anti-neoplastic nucleoside analogs resulted in continuous DNA damage/repair events at enhancers each resolving within 1-2 hours, but ultimately triggering neuronal cell death. This DNA damage response and toxicity was dependent on TDG activity. Thus, TET-mediated active DNA demethylation promotes endogenous DNA damage at regulatory elements, a process which normally contributes to cell identity but can also provoke neurotoxicity following anti-cancer treatments.
2022-12-01 | GSE210316 | GEO
Project description:Neurons harbor high levels of endogenous single strand DNA breaks (SSBs) that are targeted to neuronal enhancers and correlate with marks of DNA demethylation. To determine the source of SSBs at neuronal enhancers, we depleted the thymidine DNA glycosylase TDG, which excises TET-mediated oxidized methylcytidines 5fC and 5caC, to produce unmodified C. In differentiating neurons, induced degradation of TDG led to the disappearance of SSBs, demonstrating the existence of ongoing TET‑mediated oxidation. Using an independent model of macrophage differentiation from reprogrammed pre-B cells, we demonstrate that TET/TDG-mediated active demethylation may be a general mechanism underlying post-mitotic lineage specification. We find that macrophage differentiation prefers short patch base excision repair (SP-BER) to fill-in single nucleotide gaps, whereas neurons also frequently utilize the long-patch (LP-BER) sub-pathway. By measuring the distribution of SSBs relative to sites of oxidized cytosine, we observed that stretches of 2-30 bases are synthesized distal from the methylated CpG site during repair. Disrupting gap-filling using anti-neoplastic nucleoside analogs resulted in continuous DNA damage/repair events at enhancers each resolving within 1-2 hours, but ultimately triggering neuronal cell death. This DNA damage response and toxicity was dependent on TDG activity. Thus, TET-mediated active DNA demethylation promotes endogenous DNA damage at regulatory elements, a process which normally contributes to cell identity but can also provoke neurotoxicity following anti-cancer treatments.
2022-12-01 | GSE210314 | GEO
Project description:Neurons harbor high levels of endogenous single strand DNA breaks (SSBs) that are targeted to neuronal enhancers and correlate with marks of DNA demethylation. To determine the source of SSBs at neuronal enhancers, we depleted the thymidine DNA glycosylase TDG, which excises TET-mediated oxidized methylcytidines 5fC and 5caC, to produce unmodified C. In differentiating neurons, induced degradation of TDG led to the disappearance of SSBs, demonstrating the existence of ongoing TET‑mediated oxidation. Using an independent model of macrophage differentiation from reprogrammed pre-B cells, we demonstrate that TET/TDG-mediated active demethylation may be a general mechanism underlying post-mitotic lineage specification. We find that macrophage differentiation prefers short patch base excision repair (SP-BER) to fill-in single nucleotide gaps, whereas neurons also frequently utilize the long-patch (LP-BER) sub-pathway. By measuring the distribution of SSBs relative to sites of oxidized cytosine, we observed that stretches of 2-30 bases are synthesized distal from the methylated CpG site during repair. Disrupting gap-filling using anti-neoplastic nucleoside analogs resulted in continuous DNA damage/repair events at enhancers each resolving within 1-2 hours, but ultimately triggering neuronal cell death. This DNA damage response and toxicity was dependent on TDG activity. Thus, TET-mediated active DNA demethylation promotes endogenous DNA damage at regulatory elements, a process which normally contributes to cell identity but can also provoke neurotoxicity following anti-cancer treatments.
2022-12-01 | GSE210313 | GEO
Project description:Neurons harbor high levels of endogenous single strand DNA breaks (SSBs) that are targeted to neuronal enhancers and correlate with marks of DNA demethylation. To determine the source of SSBs at neuronal enhancers, we depleted the thymidine DNA glycosylase TDG, which excises TET-mediated oxidized methylcytidines 5fC and 5caC, to produce unmodified C. In differentiating neurons, induced degradation of TDG led to the disappearance of SSBs, demonstrating the existence of ongoing TET‑mediated oxidation. Using an independent model of macrophage differentiation from reprogrammed pre-B cells, we demonstrate that TET/TDG-mediated active demethylation may be a general mechanism underlying post-mitotic lineage specification. We find that macrophage differentiation prefers short patch base excision repair (SP-BER) to fill-in single nucleotide gaps, whereas neurons also frequently utilize the long-patch (LP-BER) sub-pathway. By measuring the distribution of SSBs relative to sites of oxidized cytosine, we observed that stretches of 2-30 bases are synthesized distal from the methylated CpG site during repair. Disrupting gap-filling using anti-neoplastic nucleoside analogs resulted in continuous DNA damage/repair events at enhancers each resolving within 1-2 hours, but ultimately triggering neuronal cell death. This DNA damage response and toxicity was dependent on TDG activity. Thus, TET-mediated active DNA demethylation promotes endogenous DNA damage at regulatory elements, a process which normally contributes to cell identity but can also provoke neurotoxicity following anti-cancer treatments.
2022-12-01 | GSE210315 | GEO