title: Dynamics of the HP1β-PCNA-containing complexes in DNA replication and repair.
abstract: Heterochromatin protein 1 (HP1), a small non-histone chromosomal protein, was recently shown to form a complex in vivo with Proliferating Cell Nuclear Antigen (PCNA), a key factor in DNA replication. The complex, which requires HP1β in a form of a dimer, is engaged in DNA repair and replication. We now provide further evidence based on FRET-FLIM live cell studies confirming the association and close proximity between HP1β and PCNA in the complex. We also demonstrate using FRAP, that although HP1β-PCNA complexes are highly mobile in nonreplicating nuclei, when engaged in DNA replication, they become bound and do not exchange with the mobile pool. These observations are in agreement with a notion that a subpopulation of HP1 molecules interact with PCNA in vivo during DNA replication. Similarly, HP1β which is associated with PCNA in regions of DNA repair, is bound and does not exchange with the mobile pool, suggesting that HP1β in association with PCNA may be a component of a DNA repair complex.
authors: Division of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
authors: Dominika O
authors: DO
authors: Trembecka-Lucas
authors: Aleksander T
authors: AT
authors: Szczurek
authors: Jurek W
authors: JW
authors: Dobrucki
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D056504:Chromatin Assembly Factor-1 / Q000378:metabolism; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D006367:HeLa Cells; D006801:Humans; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D014157:Transcription Factors
chemical_list: C000715593:CBX1 protein, human; C489780:CNOT8 protein, human; D056504:Chromatin Assembly Factor-1; D002868:Chromosomal Proteins, Non-Histone; D018809:Proliferating Cell Nuclear Antigen; D021122:Protein Subunits; D014157:Transcription Factors; D000090266:Chromobox Protein Homolog 5; D004247:DNA
keywords: DNA repair; DNA replication; FRAP; FRET-FLIM; HP1β; PCNA; protein interactions