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In vivo dynamics of chromatin-associated complex formation in mammalian nucleotide excision repair.

ABSTRACT: Chromatin is the substrate for many processes in the cell nucleus, including transcription, replication, and various DNA repair systems, all of which require the formation of multiprotein machineries on the chromatin fiber. We have analyzed the kinetics of in vivo assembly of the protein complex that is responsible for nucleotide excision repair (NER) in mammalian cells. Assembly is initiated by UV irradiation of a small area of the cell nucleus, after which the accumulation of GFP-tagged NER proteins in the DNA-damaged area is measured, reflecting the establishment of the dual-incision complex. The dynamic behavior of two NER proteins, ERCC1-XPF and TFIIH, was studied in detail. Results show that the repair complex is assembled with a rate of approximately 30 complexes per second and is not diffusion limited. Furthermore, we provide in vivo evidence that not only binding of TFIIH, but also its helicase activity, is required for the recruitment of ERCC1-XPF. These studies give quantitative insight into the de novo assembly of a chromatin-associated protein complex in living cells.

SUBMITTER: Mone MJ

PROVIDER: S-EPMC528744 | biostudies-other | 2004 Nov

REPOSITORIES: biostudies-other

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Modulation of nucleotide excision repair by mammalian SWI/SNF chromatin-remodeling complex.

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INO80 chromatin remodeling complex promotes the removal of UV lesions by the nucleotide excision repair pathway.

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Project description:Nucleic acids can fold into G-quadruplex (G4) structures that can fine tune biological processes. Proteins are required to recognize G4 structures and coordinate their function. We identify Zuo1 as a novel G4-binding protein in a yeast one-hybrid screen. Biochemical and molecular experiments in yeast confirm that Zuo1 specifically binds to G4 structures in vitro and in vivo. In vivo in the absence of Zuo1 less G4 structures form, cell growth slows and cells become UV sensitive. Subsequent experiments reveal that these cellular changes are due to reduced levels of G4 structures. Interestingly, Zuo1 function and binding to G4 structures results in the recruitment of nucleotide excision repair (NER) factors, which has a positive effect on genome stability. Cells lacking functional NER as well as Zuo1 accumulate G4s structures, which become accessible for translesion synthesis. Our results suggest a model in which Zuo1 supports NER function and regulates the choice of the DNA repair pathway near G4 structures.

2020-06-23 | GSE149502 | GEO

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Zuo1 supports G4 structure formation and directs repair toward nucleotide excision repair.

Project description:Nucleic acids can fold into G-quadruplex (G4) structures that can fine-tune biological processes. Proteins are required to recognize G4 structures and coordinate their function. Here we identify Zuo1 as a novel G4-binding protein in vitro and in vivo. In vivo in the absence of Zuo1 fewer G4 structures form, cell growth slows and cells become UV sensitive. Subsequent experiments reveal that these cellular changes are due to reduced levels of G4 structures. Zuo1 function at G4 structures results in the recruitment of nucleotide excision repair (NER) factors, which has a positive effect on genome stability. Cells lacking functional NER, as well as Zuo1, accumulate G4 structures, which become accessible to translesion synthesis. Our results suggest a model in which Zuo1 supports NER function and regulates the choice of the DNA repair pathway nearby G4 structures.

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Chromatin remodelling complex RSC promotes base excision repair in chromatin of Saccharomyces cerevisiae.

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