title: Real-time imaging of Huntingtin aggregates diverting target search and gene transcription.
abstract: The presumptive altered dynamics of transient molecular interactions in vivo contributing to neurodegenerative diseases have remained elusive. Here, using single-molecule localization microscopy, we show that disease-inducing Huntingtin (mHtt) protein fragments display three distinct dynamic states in living cells - 1) fast diffusion, 2) dynamic clustering and 3) stable aggregation. Large, stable aggregates of mHtt exclude chromatin and form 'sticky' decoy traps that impede target search processes of key regulators involved in neurological disorders. Functional domain mapping based on super-resolution imaging reveals an unexpected role of aromatic amino acids in promoting protein-mHtt aggregate interactions. Genome-wide expression analysis and numerical simulation experiments suggest mHtt aggregates reduce transcription factor target site sampling frequency and impair critical gene expression programs in striatal neurons. Together, our results provide insights into how mHtt dynamically forms aggregates and disrupts the finely-balanced gene control mechanisms in neuronal cells.
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.|LKS Bio-medical and Health Sciences Center, CIRM Center of Excellence, University of California, Berkeley, United States.
authors.forename: Li
authors.identifier: 0000-0002-2981-6615
authors.initials: L
authors.lastname: Li
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Peng
authors.initials: P
authors.lastname: Dong
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Wesley R
authors.initials: WR
authors.lastname: Legant
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Grimm
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.|Transcription Imaging Consortium, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Luke D
authors.initials: LD
authors.lastname: Lavis
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Betzig
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.|LKS Bio-medical and Health Sciences Center, CIRM Center of Excellence, University of California, Berkeley, United States.|Transcription Imaging Consortium, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Tjian
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.|Transcription Imaging Consortium, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Zhe
authors.identifier: 0000-0002-3592-3150
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D000071058:Huntingtin Protein / Q000032:analysis*; D051379:Mice; D000066450:Mouse Embryonic Stem Cells; D050505:Mutant Proteins / Q000032:analysis; D009474:Neurons / Q000473:pathology; D066263:Protein Aggregation, Pathological; D000072760:Single Molecule Imaging; D014157:Transcription Factors / Q000037:antagonists & inhibitors; D014158:Transcription, Genetic; D014793:Visual Cortex / Q000473:pathology
chemical_list: C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D050505:Mutant Proteins; D014157:Transcription Factors
keywords: biophysics; chromatin; chromosomes; genes; huntingtin aggregates; mouse; structural biology; transcription factors