Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0268140 (XPF)
 549 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

UV light induces DNA lesions, which are removed by nucleotide excision repair (NER). Exonuclease 1 (EXO1) is highly conserved from yeast to human and is implicated in numerous DNA metabolic pathways, including repair, recombination, replication, and telomere maintenance. Here we show that hEXO1 is involved in the cellular response to UV irradiation in human cells. After local UV irradiation, fluorescent-tagged hEXO1 localizes, together with NER factors, at the sites of damage in nonreplicating cells. hEXO1 accumulation requires XPF-dependent processing of UV-induced lesions and is enhanced by inhibition of DNA repair synthesis. In nonreplicating cells, depletion of hEXO1 reduces unscheduled DNA synthesis after UV irradiation, prevents ubiquitylation of histone H2A, and impairs activation of the checkpoint signal transduction cascade in response to UV damage. These findings reveal a key role for hEXO1 in the UV-induced DNA damage response linking NER to checkpoint activation in human cells.
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PMID:Human exonuclease 1 connects nucleotide excision repair (NER) processing with checkpoint activation in response to UV irradiation. 2180 22

Ubiquitylation of histones plays a pivotal role in DNA repair. The ubiquitin ligase Ring2 was recently shown to be the dominant ubiquitin ligase of histone H2A. In a series of experiments using the human bronchial epithelia cells (16HBE) and small interfering RNA (siRNA)-Ring2 cells exposed to benzo(a)pyrene (BaP), we measured dynamic changes in the levels of DNA damage, expressions of ubiquitinated histone H2A, and nucleotide excision repair (NER) subunit xeroderma pigmentosum (XP) groups A, C, and F (XPA, XPC, XPF). We found that in vitro exposure to BaP increased DNA damage in a time- and dose-dependent manner in 16HBE and siRNA-Ring2 cells. The results show that although decrease of Ring2 causes DNA hypersensitivity to BaP, the levels of XPA, XPC, and XPF were not affected. These results indicated that Ring2 may effect the DNA repair through other pathways but not through the expressions of NER protein.
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PMID:Role of ubiquitin protein ligase Ring2 in DNA damage of human bronchial epithelial cells exposed to benzo[a]pyrene. 2371 74

Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2) and protection of telomeres protein 1 (POT1), whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres. Depletion of H2ac led to loss of telomeric repeat sequences, the appearance of dysfunctional telomeres, and chromosomal instability, including chromosomal breaks and anaphase bridges, as well as accumulation of telomere-associated DNA damage factors in H2ac depleted cells. Additionally, knockdown of H2ac elicits an ATM-dependent DNA damage response at telomeres and depletion of XPF protects telomeres against H2ac-deficiency-induced G-strand overhangs loss and DNA damage response, and prevents chromosomal instability. These findings suggest that the H2A isotype, H2ac, plays an essential role in maintaining telomere functional integrity.
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PMID:An H2A Histone Isotype, H2ac, Associates with Telomere and Maintains Telomere Integrity. 2722 73