Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet: (A) Schematic of the recombinant TAF15 construct (residues 7–99) used for production and aggregation assays. (B) SDS–PAGE of purified TAF15(7–99) before and after tag cleavage showing a single band at the expected molecular weight. (C) Negative-stain TEM of end-state assemblies reveals unbranched, fibrillar morphologies typical of amyloid fibrils. Scale bar: 200nm. (D) Endpoint ThT fluorescence of TAF15(7–99) reactions confirms amyloid formation under the indicated conditions. Statistics: Two-tailed t-test with Welch’s correction (n=3 individual replicates). (E) ThT kinetic assays (n=3 individual replicates) at 10 µM show no detectable self-assembly over 72 h in unseeded reactions, whereas the addition of preformed TAF15 fibrils induces rapid sigmoidal growth (seeded). (F) Stability profiling of TAF15 fibrils by chemical depolymerization with urea and measured by flow-induced dispersion analysis, reports the fraction of solubilized monomer as a function of denaturant.

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: Recombinant, Construct, SDS Page, Purification, Molecular Weight, Staining, Fluorescence, Two Tailed Test, Dispersion

Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet: (A) Design and workflow of the HEK293T biosensor expressing TAF15 LCD (residues 1–200) fused to mEOS3.2. (B) Fluorescent western blot of cell lysates showing the TAF15-mEOS3.2 band in biosensor cells (absent in HEK control lysate). (C) Flow-cytometry FRET readout of cells exposed to recombinant TAF15(7–99) seeds (shown in purple, n=4 individual replicates) and to “secondary” lysates harvested from previously seeded biosensors (shown in yellow, n=6 individual replicates), versus unseeded control lysate (shown in green, n=6 individual replicates). Dose–response to recombinant seeds yields EC 50 ≈ 92 nM. (D) Confocal images of seeded biosensors showing cytoplasmic puncta with fibrillar substructure (scale bar: 20 μm); insets highlight fibril-like texture (scale bar: 5 μm). (E) TEM of sarkosyl-insoluble material extracted from seeded biosensors confirms intracellular amyloid fibril (scale bar: 800 nm). (F–H) FRAP of individual puncta: (F) pre- and post-bleach images with 10 ROI circles (scale bar: 20 μm); (G) fluorescence time courses per ROI (H) start/end intensity summary shows bleaching to background with no recovery, consistent with immobile fibrillar aggregates.

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: Expressing, Western Blot, Control, Flow Cytometry, Recombinant, Fluorescence

Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet: (A) Sequence-level amyloid propensity predicted across TAF15(1–100) from CORDAX (blue) and WALTZ (magenta), highlighting overlapping high-propensity segments. (B) Thermodynamic profiling of the patient-derived TAF15 fibril (PDB: 8ONS) maps per-residue stabilizing contributions; four stability hotspots are indicated and aligned to sequence. Endpoint ThT screening of a 27-member, 15-mer moving-window library (3-res step) spanning residues 7–99 identifies six ThT-positive windows; shaded boxes correspond to the hotspots in (B) . Statistics: One-way ANOVA with Dunnett’s multiple comparisons test (n=6 individual replicates). (D) ThT kinetics (n=3 individual replicates) of the six hit windows exhibit sigmoidal growth, color-coded to match panels (A–C). (E) TEM validates amyloid-like fibrils formed by each hit peptide; frame outlines retain the panel color code for cross-reference.

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: Sequencing, Derivative Assay, Residue

Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet: (A) ThT seeding assays of TAF15(7–99) with aggregates from each APR peptide (n=3 individual replicates). All six windows accelerate aggregation relative to unseeded control. (B) Representative confocal imaging of TAF15 biosensor cells seeded with peptide-derived aggregates, yielding punctate cytoplasmic inclusions. (C) Quantification of cellular seeding (FRET) versus peptide-seed concentration reveals dose-dependent induction of cytoplasmic inclusions (n>4 individual replicates). Dotted line indicates control averages (untreated cells).

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: Control, Imaging, Derivative Assay, Concentration Assay

Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet: (A) Electron micrographs of recombinant tau(287–391), α-synuclein, and Aβ 42 fibrils used as heterologous amyloid controls. (B) TAF15 biosensor FRET readout shows no induction by heterologous amyloids (tau, α-synuclein, Aβ 42 ) relative to TAF15 seeds, confirming molecular specificity. Statistics: Two-way ANOVA with t-tests for multiple comparison (n=4 individual replicates). Dotted line indicates control averages (untreated cells). (C-D) aFTLD-U brain lysates (n=4 individual replicates) seed the TAF15 biosensor in a concentration-dependent manner, demonstrating prion-like propagation of ex vivo TAF15 aggregates. Dotted line indicates control averages (untreated cells). (E) TEM validation of recombinant FUS fibrils displaying canonical amyloid morphology. (F) FRET quantification in the TAF15 biosensor demonstrating absence of cross-seeding by FUS aggregates (n=4 individual replicates). (G) Confocal micrographs of biosensor cells co-expressing mRuby-tagged FUS and seeded with TAF15 aggregates, showing co-localization of FUS within TAF15 inclusions.

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: Recombinant, Comparison, Control, Concentration Assay, Ex Vivo, Biomarker Discovery, Expressing

Journal: bioRxiv

Article Title: TAF15 amyloids propagate via defined motifs in a prion-like fashion

doi: 10.1101/2025.11.17.688886

Figure Lengend Snippet:

Article Snippet: All individuals selected for this study exhibited neuronal cytoplasmic inclusions and occasional vermiform neuronal intranuclear inclusions in the dentate gyrus and frontal cortex that were immunoreactive for FUS (11570-1-AP, 1:500, rabbit polyclonal, Proteintech Group) and TAF15 (A300-308A, 1:500, rabbit polyclonal, Bethyl Laboratories).

Techniques: