EMBO/soda-nel huggingface dataset:
A PBX1 transcriptional network controls dopaminergic neuron development and is impaired in Parkinson’s disease (2016)
Figure 5

Figure 5 - Identification of direct PBX1 target genes. (A) Chromatin immunoprecipitation sequencing (ChIP-seq) identified a PBX1 binding core sequence motif composed of a 10-nucleotide motif (A) and a 5-nucleotide motif (B). (B) Schematic of the track of PBX1 ChIP-seq compared to IgG ChIP-seq as a control on different loci with peaks identified by HOMER. Each locus represents a 20kb chromosome region. (C) List of the 29 most regulated genes (t-test q-value <0.05) identified by Gene Set Enrichment Analysis (GSEA) and ranked by p-value. RPKM stands for Reads Per Kilobase of transcript per Million mapped reads. GSEA was performed on genes identified by RNA-Seq as differentially expressed in the VM at E12.5 compared to adjacent brain regions and identified by PBX1 Chip-Seq in proximity to transcription starting sites. (D) Graphic representation of these top 29 genes (red dots) in the GSEA curve showing a high correlation between the cistrome and transcriptome (p-value <0.001, q-value<0.005). (E) ChIP followed by PCR confirmed that PBX1 binds to genomic regions in close proximity to the TSS of Pitx3 (Pitx3-Gbf1), Onecut2 and Nfe2l1 genes. No co-immunoprecipitation was detected for the unrelated gene, Lrp1b (Low Density Lipoprotein Receptor-Related Protein 1B). (F, G) The regulation of Pitx3 and Onecut2 by PBX1 was confirmed in Pbx1-/-;Pbx3+/- mutant embryos at E12.5, compared to wild-type (Pbx1+/+) littermates. (F) Representative immunofluorescence/confocal images showing that decreased levels of PITX3 and number of PITX3+ cells in E12.5 Pbx1-/-;Pbx3+/- embryos. This reduction is more evident in the basal plate (BP) and in the midline (M), as shown at higher magnification (right). (G) Double ONECUT2+TH+ cells were detected only in the lateral part of the mFP in E12.5 Pbx1-/-;Pbx3+/- embryos. Selected areas are magnified to the right. A scheme (right) shows the distribution of cells in Pbx1+/+ and Pbx1-/-;Pbx3+/- embryos. All scale bars, 40µm. Error bars represent mean ± standard deviation. Biological replicates (dots) per condition and p-value (T-test) are indicated in each graph.
A PBX1 transcriptional network controls dopaminergic neuron development and is impaired in Parkinson’s disease (2016)
Figure 6

Figure 6 - PBX1 promotes survival of human neural cells via NFE2L1, a pathway disrupted in PD patients. (A) Representative immunofluorescence/confocal images showing that NFE2L1 is detected in TH+ mDAn and neuroblasts at E12.5. (B) The expression of NFE2L1 in TH+ neurons is dramatically reduced in Pbx1-/-;Pbx3+/- compared to Pbx1+/+ embryos at E12.5 (C) shRNA lentiviruses against NFE2L1 increased the levels of aCASP3 in H2O2-treated (100µm for 12 hours) TH+ neurons derived from hNES cells differentiated for 8 days (percentage). White arrows indicate double TH+aCASP3+ neurons. (D) PBX1 overexpression protected TH+ neurons derived from hNES cells from the oxidative stress induced by H2O2 (100µm for 12 hours), resulting in reduced levels of aCASP3 in TH+ neurons (percentage). (E) Human postmortem SN tissue of control donors exhibited PBX1 chromogenic staining (dark-blue/black, indicated by arrowheads) in the nuclei of neuromelanin+ cells (NM+, cytosolic brown aggregates) of the SN. In contrast, PBX1 staining was severely reduced in PD patients. (F) Graphical representation of PBX1 intensity levels in the SN of NM+ neurons in all individual controls and PD patients analyzed. Each dot in the graph represents the level of PBX1 in the nuclei of one single NM+ neuron. (G) Strong immunoreactivity of the PBX1 direct target, NFE2L1, was also detected as very well defined nuclear punctuate structures in NM+ cells of the SN in control samples (arrowheads), but were dramatically reduced in PD patients. Yellow asterisks indicate the nucleoli. (H) Percentage of NM+ neurons showing nuclear NFE2L1 staining in the SN of control donors and PD patients. (I) Graphical representation of all individual controls and PD patients analyzed, showing that NM+ neurons with NFE2L1+ nuclei in the SN of PD patients are less than 10% or are totally absent. All scale bars, 40µm. Error bars represent mean ± standard deviation. For C and D, n=3. P-values (T-test) are indicated in the graphs. Dots in H represent different control donor or PD patients.
CTGF/ CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction (2020)
Figure 1

Figure 1. Interaction between the CT domain CTGF and the third β-propeller domain of LRP4 enhances the binding of LRP4 to MuSK

(A-C) Representative immunoprecipitation (IP) of HEK293 cells transfected with indicated cDNAs. (A) CTGF interacts with LRP4 but not with MuSK. Full-length CTGF (CTGF-full-myc) was immunoprecipitated with the ectodomain of LRP4 (LRP4ect-Flag, lane 6) but not with the ectodomain of MuSK (MuSKect-Flag, lane 3). However, when CTGF-full-myc, LRP4ect, and MuSKect-Flag were expressed together, CTGF-full-myc was immunoprecipitated with MuSKect-Flag (lane 5). The CT domain of CTGF (CTGF-CT-myc) was sufficient to immunoprecipitate LRP4ect-Flag (lane 7). (B) Deletion of the CT domain of human CTGF (CTGF-ΔCT_ΔTSP1 and CTGF-ΔCT) impairs the interaction between CTGF and LRP4ect-Flag. (A, B) Predicted positions of full-length and shortened CTGF proteins are indicated by bars and/or asterisks. (C) Anti-CTGF antibody immunoprecipitated human LRP4 deleted with the 1st, 2nd, and 4th β-propeller domains (Δ1, Δ2, and Δ4) but not with the 3rd β-propeller domain (∆3).

(D-E) Cell-free plate-binding assays. A purified tagged-protein was attached to a plastic plate and a purified recombinant protein fused to alkaline phosphatase (AP) was overlaid. Bound protein was quantified by measuring AP activity. (D) LRP4ect-Flag, but not MuSKect-Flag, bound to overlaid CTGF-full-mycAP and CTGF-CT-mycAP. In contrast, LRP4ect-Flag did not bind to CTGF-ΔCT-mycAP. (E, upper panel) LRP4ect-Flag bound to overlaid MuSKect-mycAP in a dose-dependent manner of CTGF-full-myc, but not of CTGF-ΔCT-myc. (E, lower panel) LRP4ect-Flag bound to overlaid agrin-mycAP independent of CTGF-full-myc. (D-E) Rspo2-mycAP and Rspo2-myc were used as Control-mycAP and control-myc, respectively. Mean and SD (n = 9 wells; 3 wells in 3 independent experiments) are indicated. p-value < 0.05 by two-way repeated measures ANOVA for the three panels in (D) and (E). p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.
CTGF/ CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction (2020)
Figure 2

Figure 2. CTGF stabilizes Lrp4 on the plasma membrane of C2C12 myotube and the embryonic muscle

(A) Representative immunoblotting of Lrp4, MuSK, Transferrin Receptor (TfR), CTGF, and β-actin in whole-cell lysates and the plasma membrane fraction of C2C12 myotubes treated with 1 pM (1 ng/ml) agrin and/or 250 pM (100 ng/ml) CTGF for 24 h. CTGF increases Lrp4 on the plasma membrane in the presence of agrin.

(B) C2C12 myotubes were treated with 1 pM agrin and/or 250 pM CTGF for 6 h. Lrp4 was immunoprecipitated (IP) with an anti-Lrp4 antibody, and phosphorylated Lrp4 was immunoblotted with an anti-phosphotyrosine (p-Tyr) antibody.

(C) Representative immunoblotting of Lrp4, MuSK, CTGF, and TfR in whole tissue lysates and the plasma membrane fraction of lower limb muscles at E18.5 of wild-type (WT) and Ctgf-/- mice.

(D) Representative immunoblotting of Y755-phosphorylated MuSK, total MuSK, and β-actin in the diaphragm at E18.5 of wild-type (WT), Ctgf-/-, and Ctgf+/- mice.

Data information: Mean and SD (n = 3 independent experiments) are indicated. p-value < 0.05 by one-way ANOVA. p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.
CTGF/ CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction (2020)
Figure 3

Figure 3. CTGF enhances agrin-mediated AChR clustering in C2C12 myotubes

(A) C2C12 myotubes were treated with indicated concentrations of agrin-mycAP, CTGF-mycAP, and/or CTGF-∆CT-mycAP for 3 h. Total MuSK was immunoprecipitated (IP) with an anti-MuSK antibody, and phosphorylated MuSK was immunoblotted with an anti-phosphotyrosine (p-Tyr) antibody. CTGF-mycAP, but not CTGF-∆CT-mycAP, enhanced agrin-mediated MuSK phosphorylation.

(B) C2C12 myotubes were treated with 5 pM agrin-mycAP, 250 pM CTGF-mycAP, and/or 250 pM CTGF-∆CT-mycAP for 18 h. BSA was added to the control medium. AChRs and the plasma membrane were visualized with Alexa594-conjugated α-bungarotoxin (red) and CellMask (green), respectively. Scale bar = 20 µm. Arrowheads point to the AChR clusters with an axis length of 4 μm or more. CTGF enhances agrin-mediated AChR clustering.

(C) C2C12 myotubes were infected with lentivirus expressing shControl, shCtgf-1, or shCtgf-2. Doxycycline was added for 2 days to induce shRNA expression. BSA or agrin was added to the medium at 10 pM. Total MuSK was immunoprecipitated (IP) by an anti-MuSK antibody, and phosphorylated MuSK was immunoblotted with an anti-phosphotyrosine (p-Tyr) antibody. Ctgf knockdown suppressed MuSK phosphorylation.

(D) Ten pM agrin was added to the medium. AChRs were visualized with Alexa594-conjugated α-bungarotoxin (red signals) in the infected myotube (green GFP signals). Ctgf knockdown decreased the number and length of AChR clusters. Scale bar = 10 µm.

Data information: Mean and SD (n = 3 independent immunoblotting experiments) are indicated in (A and C). Blinded morphometric analysis of myotube and AChR signals are shown by mean and SD (n = 60-75 myotubes in 3 independent experiments) in the right panels in (B and D). The axis length of an AChR cluster with 4 µm or more was recognized and measured by the MetaMorph software, and . p-value < 0.05 by one-way ANOVA in (A to D) except for myotube length in (D). p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.
CTGF/ CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction (2020)
Figure 4

Figure 4. Ctgf is enriched at the neuromuscular junction

(A, B) (A) Quantitative RT-PCR of Chrne, Musk, Lrp4, and Ctgf in C2C12 myotubes treated with 10 ng/ml BSA or recombinant human CTGF. (B) Quantitative RT-PCR of Ctgf in C2C12 myotubes treated with indicated combinations of 10 ng/ml agrin and/or 10 ng/ml neuregulin-1. Mean and SD (n = 3 mice) are indicated. p-value < 0.05 by two-way repeated measures ANOVA (A) and one-way ANOVA (B). p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.

(C) Localizations of CTGF and AChR in a representative cross section of the lower limb muscle at E18.5. Co-localization of AChR (red) and CTGF (green) is indicated in the merged images. Red arrow points to an AChR cluster. Scale bar = 20 μm.

(D) Quantitative RT-PCR of Ctgf and neural Agrn in the spinal cord and the diaphragm in mouse. Mean and SD (n = 3 mice) are indicated. p-value < 0.05 by two-way repeated measures ANOVA. p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.
CTGF/ CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction (2020)
Figure 5

Figure 5. Apposition of the nerve terminal and the motor endplate is compromised in the E18.5 diaphragm of Ctgf-/- mice

(A) Representative confocal images of the left diaphragm at E18.5 labeled with α-bungarotoxin (red) and anti-peripherin antibody (green) to visualize AChRs and the motor axon, respectively. The endplates of Ctgf-/- diaphragm were smaller (lower left panel) than those of the wild-type diaphragm (upper left panel). In the Ctgf-/- diaphragm, 10.0 ± 3.2% (mean and SD, n = 105 in 5 embryos) of peripherin-positive axons passed through the AChR-positive areas. In contrast, in the wild-type diaphragm, 2.0 ± 1.4% (mean and SD, n = 102 in 5 embryos) of peripherin-positive axons passed through the AChR-positive areas. Quantification was performed in a blinded manner. Scale bar = 5 µm.

(B) Representative confocal images of the left diaphragm at E18.5 labeled with α-bungarotoxin (red) and anti-synaptophysin antibody (green) to visualize AChRs and the nerve terminal, respectively. Synaptophysin signals mostly overlapped with α-bungarotoxin signals in the wild-type diaphragm, whereas synaptophysin signals extended into the axon in the Ctgf-/- diaphragm. Scale bar = 5 µm.

(C-E) Blinded morphometric analysis of AChR signals (C), synaptophysin signals (D), and the ratio of synaptophysin signals not colocalized with AChR signals (E) of confocal images shown in (A) and (B). AChR areas (C), but not synaptophysin-positive areas (D), were decreased in Ctgf-/- mice at E18.5. (E) A large fraction of synaptophysin signalswere not colocalized with AChR signals in Ctgf-/- diaphragm. Mean and SD (n = 40-50 NMJs in 6 left diaphragms) are indicated. p-value < 0.05 by one-way ANOVA for (C and E), but not for (D). p < 0.05 by post-hoc Tukey test is indicated by a single letter representing each group.

(F) Representative electron micrographs of the NMJs in the diaphragm of wild-type and Ctgf-/- mice at E18.5. In Ctgf-/- mice, synaptic vesicles are sparser and the number of mitochondria at the nerve terminals is reduced compared to those in wild-type mice. See Table 1 for morphometric analysis. Regions indicated by rectangles are enlarged in the insets. Arrowheads point to synaptic vesicles (SV). Mit, mitochondria. Blinded morphometric measurements are shown in Table 1. Scale bar = 500 nm.

(G) Schematic showing binding of CTGF to the agrin/Lrp4/MuSK complex and induction of acetylcholine receptor (AChR) clustering at the neuromuscular junctions. The CT domain of CTGF binds to the 3rd β-propeller domain of LRP4 to enhances binding of LRP4 to MuSK, and facilitates agrin-mediated MuSK phosphorylation and AChR clustering.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 1

TFG octamers assemble into a cup‐like structure in vitro

Montage of class averages and 3D volumes of human TFG (amino acids 1‐193; EMDataBank accession code EMD‐6076). Two sets of 2D class averages and 3D volumes are shown with the left columns showing the class averages generated by reference‐free alignment and classification and the right columns showing 3D RCT volumes corresponding to the class average to the left. Scale bars, 50 Å.
Montage of class averages and 3D volumes of C. elegans TFG (amino acids 1‐195; EMDataBank accession code EMD‐6075), generated as described in (A). Scale bars, 50 Å.
Superposition of 3D volumes of full‐length human TFG and truncated TFG (amino acids 1‐193). The truncated form is depicted in yellow, while the full‐length form is depicted as gray mesh. The top view (top) exhibits limited differences in the structures, while the side view (bottom) shows extra density in the full‐length TFG isoform. Scale bar, 25 Å.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 2

The PQ‐rich domain of TFG facilitates its further polymerization

TFG particle size was determined using dynamic light scattering under increasing potassium acetate concentrations. Error bars represent mean ± SEM; n = 10 replicates.
Confocal images of recombinant, BODIPY‐labeled TFG in the presence of varying potassium acetate concentrations. Scale bar, 2 μm.
Recombinant TFG in the presence of varying potassium acetate concentrations was imaged by negative stain‐EM. Large arrowheads highlight TFG polymers (only found in the presence of elevated potassium acetate). Small arrowheads highlight individual 11 nm cup‐like TFG octamers. Scale bar, 30 nm.
Circular dichroism spectroscopy was used to characterize the carboxyl‐terminus of C. elegans TFG (amino acids 195‐486). Samples were analyzed at different concentrations, and the data were normalized relative to one another. CD spectra were collected at 25°C in 25 mM sodium phosphate (pH 7.2) using a 1 mm path length quartz cell. The spectra are characteristic of an intrinsically disordered protein.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 3

TFG accumulates at the ER/ERGIC interface in mammalian cells

The distributions of endogenous TFG and ERGIC‐53 were examined in hTERT‐immortalized RPE‐1 cells stably expressing low levels of mApple‐Sec16B using SR‐SIM (more than 15 cells analyzed on 3 separate occasions). Scale bar, 5 μm. Inset scale bar, 1 μm.
Cells stably expressing low levels of GFP‐Sec16B and mRuby‐Sec23A (Sec23A) were fixed and imaged using SR‐SIM (n = 12). Scale bar, 5 μm. Inset scale bar, 1 μm.
The distribution of endogenous TFG was examined in cells stably expressing low levels of mRuby‐Sec23A (Sec23A) using SR‐SIM (n = 10). Scale bar, 5 μm. Inset scale bar, 1 μm.
The distributions of endogenous TFG and Sec31A were examined using g‐STED (n = 8). Scale bar, 1 μm.
The distributions of endogenous TFG and Sec31A were examined using immunogold EM. Large arrowheads highlight 15 nm gold particles bound to α‐TFG antibodies. The small arrowhead highlights 5 nm gold particles bound to α‐Sec31A antibodies. At least 15 different cells were examined, and representative images are shown. Scale bar, 100 nm.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 4

The PQ‐rich domain of TFG is required for its distribution at the ER/ERGIC interface

A Cells depleted of endogenous TFG were transfected with a variety of TFG transgenes (including full‐length, untagged TFG, a truncation mutant encoding amino acids 1‐300 of untagged TFG, and a truncation mutant encoding amino acids 1‐350 of untagged TFG) and stained using α‐TFG and α‐Sec31A antibodies. Scale bar, 5 μm. Inset scale bar, 1 μm. Images shown are representative of at least 15 individual cells analyzed for each condition.
B A recombinant polyhistidine‐ and SUMO‐tagged TFG fragment (Sumo‐TFGc, amino acids 194‐400; total molecular mass of 42 kDa) was expressed and purified from Escherichia coli extracts using nickel affinity resin. Coomassie‐stained gels of the peak elution fractions after separation of the recombinant protein on a S200 gel filtration column (top) or a 10–30% glycerol gradient (bottom) are shown. To determine the native molecular weight of the protein, the following equation was used: M = 6πηNas/(1 − υρ), where M is the native molecular weight, η is the viscosity of the medium, N is Avogadro's number, a is the Stokes radius, s is the sedimentation value, υ is the partial specific volume, and ρ is the density of the medium (Siegel Monty, ). These data suggest that this fragment of TFG is capable of forming dimers in solution.
C, D Control cells (C) or cells depleted of endogenous TFG (D) were transfected with a construct expressing TFG with a carboxyl‐terminal GFP tag and stained using α‐Sec31A antibodies. Scale bar, 5 μm. Images shown are representative of at least 20 individual cells analyzed for each condition.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 5

TFG depletion disrupts early secretory pathway organization

Human RPE‐1 cells were mock‐transfected (control) or transfected with a TFG siRNA for 60 h. Cells were fixed and stained using α‐Sec16A and α‐Sec31 antibodies and imaged using confocal microscopy. Images shown are projections of 3D data sets (4 μm in z). Both individual and merged images with Sec16A in green and Sec31A in red are shown (at least 15 cells for each condition). Scale bar, 5 μm. Higher magnification views of the indicated regions (boxed) are also shown in the lower or upper right portion of each image. Inset scale bar, 1 μm.
Quantification of the number of Sec31A‐labeled structures in a 4 μm2 region. For both conditions (control or TFG siRNA‐treated), at least 50 distinct regions away from the peri‐nuclear Golgi were examined. Error bars represent mean ± SEM; at least 15 different cells per condition. **P 0.01 compared with control, calculated using a paired t‐test.
Quantification of the number of Sec16A‐labeled structures in a 4 μm2 region. For both conditions (control or TFG siRNA‐treated), at least 50 distinct regions away from the peri‐nuclear Golgi were examined. Error bars represent mean ± SEM; at least 15 different cells per condition. No statistically significant difference was observed, following analysis using a paired t‐test.
Cells stably expressing low levels of GFP‐ERGIC‐53 and mRuby‐Sec23A were fixed and imaged using SR‐SIM (top), or depleted of endogenous TFG prior to fixation and SR‐SIM imaging (bottom). Images shown are representative of at least 15 individual cells analyzed for each condition. Scale bar, 5 μm. Inset scale bar, 1 μm.
Human RPE‐1 cells were mock‐transfected (control) or transfected with a TFG siRNA for 60 h. Cells were fixed and stained using α‐Sec16A and α‐ERGIC‐53 antibodies and imaged using SR‐SIM. Images shown are projections of 3D data sets (4 μm in z). Both individual and merged images with Sec16A in green and ERGIC‐53 in red are shown (at least 15 cells for each condition). Scale bar, 5 μm. Higher magnification views of the indicated regions (boxed) are also shown in the lower or upper right portion of each image. Arrowheads highlight Sec16A‐labeled structures that do not exhibit juxtaposed ERGIC‐53 staining. Inset scale bar, 1 μm.
Based on structured illumination microscopy, quantification of the number of Sec16A‐labeled structures juxtaposed (within 500 nm) to ERGIC‐53‐labeled structures is shown. For both conditions (control or TFG siRNA‐treated), at least 1,000 unique Sec16A‐labeled structures were examined. Error bars represent mean ± SEM; at least 15 different cells per condition. **P 0.01 compared with control, calculated using a paired t‐test.
TFG clusters COPII‐coated transport carriers and promotes early secretory pathway organization (2014)
Figure 6

TFG depletion delays de novo Golgi assembly

Human RPE‐1 cells stably expressing low levels of mannosidase II‐mApple (ManII‐mApple) were mock‐transfected (control) or transfected with a TFG siRNA for 60 h, then fixed and stained using TFG antibodies and imaged using confocal microscopy. Alternatively, cells were either treated with DMSO (top row) or brefeldin A (BFA) for 1 h (middle row), followed by fixation, or washed into fresh media following DMSO or BFA treatment for 30 min (bottom row), prior to fixation. Images shown are projections of 3D data sets (4 μm in z). Merged images with TFG in green and ManII in red are shown. Scale bar, 5 μm. Images shown are representative of at least 10 individual cells analyzed for each condition.
Human RPE‐1 cells were mock‐transfected (control) or transfected with a TFG siRNA for 60 h, then fixed and stained using TFG and GM130 antibodies and imaged using confocal microscopy. Alternatively, cells were either treated with DMSO (top row) or brefeldin A (BFA) for 1 h (middle row), followed by fixation, or washed into fresh media following DMSO or BFA treatment for 30 min (bottom row), prior to fixation. Images shown are projections of 3D data sets (4 μm in z). Merged images with TFG in green and GM130 in red are shown. Scale bar, 5 μm. Images shown are representative of at least 10 individual cells analyzed for each condition.
Higher magnification views of the indicated regions in (B, boxed) are shown (GM130 distribution only). Scale bar, 2 μm.