title: Dynamics of the ternary complex formed by c-Myc interactor JPO2, transcriptional co-activator LEDGF/p75, and chromatin.
abstract: Lens epithelium-derived growth factor (LEDGF/p75) is a transcriptional co-activator involved in targeting human immunodeficiency virus (HIV) integration and the development of MLL fusion-mediated acute leukemia. A previous study revealed that LEDGF/p75 dynamically scans the chromatin, and upon interaction with HIV-1 integrase, their complex is locked on chromatin. At present, it is not known whether LEDGF/p75-mediated chromatin locking is typical for interacting proteins. Here, we employed continuous photobleaching and fluorescence correlation and cross-correlation spectroscopy to investigate in vivo chromatin binding of JPO2, a LEDGF/p75- and c-Myc-interacting protein involved in transcriptional regulation. In the absence of LEDGF/p75, JPO2 performs chromatin scanning inherent to transcription factors. However, whereas the dynamics of JPO2 chromatin binding are decelerated upon interaction with LEDGF/p75, very strong locking of their complex onto chromatin is absent. Similar results were obtained with the domesticated transposase PogZ, another cellular interaction partner of LEDGF/p75. We furthermore show that diffusive JPO2 can oligomerize; that JPO2 and LEDGF/p75 interact directly and specifically in vivo through the specific interaction domain of JPO2 and the C-terminal domain of LEDGF/p75, comprising the integrase-binding domain; and that modulation of JPO2 dynamics requires a functional PWWP domain in LEDGF/p75. Our results suggest that the dynamics of the LEDGF/p75-chromatin interaction depend on the specific partner and that strong chromatin locking is not a property of all LEDGF/p75-binding proteins.
authors.affiliation: From the Laboratory for Photochemistry and Spectroscopy, Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
authors.forename: Jelle
authors.initials: J
authors.lastname: Hendrix
authors.forename: Bart
authors.initials: B
authors.lastname: van Heertum
authors.forename: Els
authors.initials: E
authors.lastname: Vanstreels
authors.forename: Dirk
authors.initials: D
authors.lastname: Daelemans
authors.forename: Jan
authors.initials: J
authors.lastname: De Rijck
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D018613:Microscopy, Confocal; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D019895:Transposases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D018797:Cell Cycle Proteins
chemical_list: D002843:Chromatin; D049452:Green Fluorescent Proteins; D036341:Intercellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D012097:Repressor Proteins; D019895:Transposases; C513450:CDCA7L protein, human; C541037:POGZ protein, human; D004268:DNA-Binding Proteins; D018797:Cell Cycle Proteins; C119380:lens epithelium-derived growth factor
keywords: Chromatin; Coactivator Transcription; Fluorescence Correlation Spectroscopy; Integrase; JPO2; LEDGF/p75; PogZ; Protein Dynamics; Protein-Protein Interactions; Transcription Factors