Journal: Cell reports

Article Title: Uncovering genetic interactions in the DNA repair network in response to endogenous damage and ionizing radiation

doi: 10.1016/j.celrep.2025.116850

Figure Lengend Snippet: (A) Distribution of the observed phenotypes depleted in the basal screen results, indicating where the MRE11A-UBR5 gene pair falls relative to other depleted interactions. (B) Ranked observed phenotypes from the basal screen for both UBR5 and MRE11A . Blue/red regions highlight significantly enriched/depleted UBR5 -gene and MRE11A -gene interactions, respectively. Blue and red regions highlight gene combinations that are enriched above (blue) or depleted below (red) one standard deviation (+0.6981 and −0.7791) of the mean of all basal interactions and possess a Fisher-combined p < 0.05. (C) Time-lapse images of growth from Dox-induced dual-guide vectors with NT-1 x UBR5 -g2 or NT-1 x NT-2 in nuclear-EGFP-expressing cells co-cultured with nuclear-RFP-expressing cells grown in DMSO or 6.25 μM mirin (+mirin). Images are from one well per condition over the first 72 h of growth. Scale bar: 100 μM. (D) Measurements are calculated as the log 2 fold change (log 2 FC) of Dox induced over uninduced growth for the labeled condition, relative to the growth of co-cultured RFP+ cells, as seen in (C). Data represent mean ± SEM of 3 biological repliactes. The gray bar indicates the 72 h of growth shown in (C), though imaging continued. (E) Comparative growth differences at 96 h of two separate, inducible UBR5 guides from experiments performed similarly to those shown in (C) and (D). Bars are only shown for Dox-treated conditions but are normalized to uninduced, DMSO-treated control wells for each genotype and replicate. Mirin: 5 μM. Blue prediction bars are calculated from an additive model assuming no interaction, with the average effect of mirin on NT cells plus the average effect of UBR5 depletion for each guide and replicate. Data represent mean ± SEM of 2 biological replicates, and statistics represent a two-way ANOVA with Dunnett multiple comparisons test; p = 0.0277. (F) Western blot depicting robust UBR5 KO in two selected HT1080-6TG clones. (G) Dose curve of HT1080-6TG clones shown in (F) grown in increasing doses of mirin in a colony formation assay. IC50 was calculated from a sigmoidal interpolation of all datasets. Error bars: ± SEM from three biological replicates. Statistics match in color the clone they reference, relative to NT cells. Statistics: a two-way ANOVA with Dunnett’s multiple comparisons test between NT-treated cells and UBR5 -KO clones at each concentration; * p < 0.01 and **** p < 0.0001. (H) Western blot showing UBR5 depletion in U2-OS cells electroporated with either an sgNT-RNP or an sg UBR5 -RNP. (I) Log 2 of the relative confluence over time (relative to DMSO) for sgNT-RNP- or sg UBR5 -RNP-treated U2-OS cells from (H), grown with 25 μM mirin over 120 h. The shaded area around each solid line indicates the SEM from three biological replicates. Statistics: a two-way ANOVA at 120 h with Šídák’s multiple comparisons test; p = 0.0317. See also .

Article Snippet: U2-OS , ATCC , HTB-96.

Techniques: Standard Deviation, Expressing, Cell Culture, Labeling, Imaging, Control, Western Blot, Clone Assay, Colony Assay, Concentration Assay

Journal: Nature Communications

Article Title: Supercharging-enhanced nDIA-MS enables global profiling of drug-induced proteome solubility shifts

doi: 10.1038/s41467-026-69025-8

Figure Lengend Snippet: Volcano plots showing the comparisons of protein levels between MG132 vs vehicle, and MG132 + ML-792 vs ML-792 from ( A ) U2OS, ( B ) HeLa, and ( C ) HEK293A cells. Volcano plots showing the comparisons of protein levels between ML-792 vs vehicle, and MG132 + ML-792 vs MG132 from ( D ) U2OS, ( E ) HeLa, and ( F ) HEK293A cells. P -values were calculated using a two-tailed Student’s t-test. No adjustments for multiple comparisons were applied. G Venn diagram showing the overlaps of up- and down-regulated proteins obtained from three cancer cell lines following treatment of MG132. Differentially regulated proteins from two pairwise comparisons of MG132 vs vehicle and MG132 + ML-792 vs ML-792 were combined. H Venn diagram showing the overlaps of up- and down-regulated proteins obtained from three cancer cell lines following treatment of ML-792. I , J Heatmaps showing differential proteins modulated by MG132 ( I ) and ML792 ( J ), respectively. Only proteins dysregulated in at least two cell lines are displayed. Western blotting results of representative proteins modulated by MG132 or ML792, including C-FOS ( K ), EGR1 ( K ), CCN1/2 ( L ), HIF1A ( M ). Experiments were repeated at least three times, and similar results were obtained. Source data are provided as a Source Data file.

Article Snippet: U2OS cells were purchased from the ATCC (Manassas, VA) and maintained in McCoy’s 5 A (Modified) medium containing 10% fetal calf serum at 37 °C with 5% CO 2 .

Techniques: Two Tailed Test, Western Blot

Journal: Nature Communications

Article Title: Supercharging-enhanced nDIA-MS enables global profiling of drug-induced proteome solubility shifts

doi: 10.1038/s41467-026-69025-8

Figure Lengend Snippet: Volcano plots showing the comparisons of relative insolubility rates between MG132 vs vehicle, and MG132 + ML-792 vs ML-792 from ( A ) U2OS, ( B ) HeLa, and ( C ) HEK293A cells. P -values were calculated using a two-tailed Student’s t-test. No adjustments for multiple comparisons were applied. Venn diagram showing the overlaps of ( D ) up- and ( E ) down-regulated proteins obtained from three cancer cell lines. Differentially regulated proteins from two pairwise comparisons of MG132 vs vehicle and MG132 + ML-792 vs ML-792 were combined. Functional enrichment analysis of the proteins whose insolubility rates were consistently ( F ) up- and ( G ) down-regulated in at least two cell lines. Enrichment analysis was performed using DAVID with default settings. P-values were calculated using the modified Fisher’s exact test (EASE score). No adjustments for multiple comparisons were applied. H–J Heatmaps showing proteins modulated by MG132. K–M Western blotting result of representative proteins that modulated by MG132 or ML792, including BAG6, UBL4A, TEX264, HSF1, REV1, and ATR1. Experiments were repeated at least three times, and similar results were obtained. Source data are provided as a Source Data file.

Article Snippet: U2OS cells were purchased from the ATCC (Manassas, VA) and maintained in McCoy’s 5 A (Modified) medium containing 10% fetal calf serum at 37 °C with 5% CO 2 .

Techniques: Two Tailed Test, Functional Assay, Modification, Western Blot

Journal: Nature Communications

Article Title: Supercharging-enhanced nDIA-MS enables global profiling of drug-induced proteome solubility shifts

doi: 10.1038/s41467-026-69025-8

Figure Lengend Snippet: Volcano plots showing the comparisons of relative insolubility rates between ML-792 vs vehicle, and MG132 + ML-792 vs MG132 from ( A ) U2OS, ( B ) HeLa, and ( C ) HEK293A cells. P -values were calculated using a two-tailed Student’s t-test. No adjustments for multiple comparisons were applied. Venn diagram showing the overlaps of ( D ) up- and ( E ) down-regulated proteins obtained from three cancer cell lines. Differentially regulated proteins from two pairwise comparisons of ML-792 vs vehicle and MG132 + ML-792 vs MG132 were combined. F Functional enrichment analysis of the proteins whose insolubility rates were consistently up- and down-regulated in at least two cell lines. Enrichment analysis was performed using DAVID with default settings. P-values were calculated using the modified Fisher’s exact test (EASE score). No adjustments for multiple comparisons were applied. G–I Heatmaps showing proteins modulated by ML-792. J–L Western blotting result of representative proteins that modulated by MG132 or ML792, including FANCD2, POLR3G, SP100, and DAXX. Experiments were repeated at least three times, and similar results were obtained. Source data are provided as a Source Data file.

Article Snippet: U2OS cells were purchased from the ATCC (Manassas, VA) and maintained in McCoy’s 5 A (Modified) medium containing 10% fetal calf serum at 37 °C with 5% CO 2 .

Techniques: Two Tailed Test, Functional Assay, Modification, Western Blot

Journal: Molecular and Cellular Biology

Article Title: General Transcriptional Coactivator PC4 Activates p53 Function

doi: 10.1128/mcb.24.5.2052-2062.2004

Figure Lengend Snippet: FIG. 2. PC4 directly interacts with p53 in vitro and in vivo. (A) Induction of p53 expression in the U2OS cell line. The levels of p53 and PC4 present in adriamycin (2 g/ml)-treated U2OS cells were assessed by Western blotting using anti-p53 (upper panel) and anti-PC4 (lower panel) antibodies. (B and C) In vivo interaction of PC4 with p53. (B) Lane 1, an adriamycin (2 g/ml)-induced U2OS cell extract was immunoblotted with polyclonal PC4 antibody N17. Lane 2, immunoprecipitation of endogenous PC4 from an induced U2OS cell lysate was performed using anti-p53 monoclonal antibody DO1 followed by immunoblotting with anti-PC4 polyclonal antibody. Lane 3, immunoprecipitation using mouse preimmune serum used as a control. (C) Lane 1, immunoprecipitation of endogenous p53 from an induced U2OS cell extract, using anti-PC4 polyclonal antibody N17 followed by immunoblotting with anti-p53 monoclonal antibody DO1. Lane 2, adriamycin-induced U2OS cell extract immunoblotted with monoclonal p53 antibody DO1. Lane 3, immunoprecipitation reaction with goat preimmune serum used as a control. (D, E, and F) Interaction of PC4 with p53 in an in vitro GST pulldown assay. (D) Schematic representation of GST and GST-p53 fusion proteins. , strong interaction of PC4 with respective GST-p53 fusion protein; , weaker interaction; , no interaction. (E) SDS-PAGE (10%) and Coomassie blue R250 staining of immobilized GST-p53 fusion proteins. Lane 1, GST-p53 (full length); lane 2, GST-p53(1-73), lane 3, GST-p53(120-290); lane 4, GST-p53(284- 330), lane 5, GST-p53(328-368); lane 6, GST-p53(364-393). GST fusion proteins predominantly contain intact proteins (indicated with asterisks) with minimum low-molecular-weight breakdown products. (F) One microgram of GST (lane 2) or GST-p53 fusion proteins (lanes 3 to 8) was incubated with bacterial extract containing 200 ng of PC4 and analyzed by immunoblotting with anti-PC4 N17 antibody. Lane 1, 5% input of bacterial cell lysate. IP, immunoprecipitation; IB, immunoblot; WCE, whole-cell extract; AD, activation domain; DBD, DNA binding domain; OD, oligomerization domain.

Article Snippet: Immunoprecipitation was performed by incubating the drug-treated U2OS cell lysate with protein A-agarose beads conjugated to either anti-p53 mouse monoclonal antibody DO1 (Oncogene) or anti-PC4 goat polyclonal antibody N17 (Santa Cruz).

Techniques: In Vitro, In Vivo, Expressing, Western Blot, Immunoprecipitation, Control, GST Pulldown Assay, SDS Page, Staining, Molecular Weight, Incubation, Activation Assay, Binding Assay

Journal: Bone Research

Article Title: Chemotherapeutic drug-triggered AEP-cleaved G3BP1 orchestrates stress granules/nucleoli/mitochondria in osteosarcoma

doi: 10.1038/s41413-025-00453-w

Figure Lengend Snippet: Chemotherapeutic drugs induced SG assembly and triggered AEP to specifically cleave G3BP1 at N258/N309. a Representative immunofluorescences (IF) images of SG assembly in U2OS, 143B, U87-MG and A549 cells exposed to cisplatin (5 and 50 μmol/L) or vehicle for 6 h. Scale Bar = 10 μm. b Quantification of the counts of SGs per cell ( n = 50) and SG + cell ratio ( n = 6) in cells of ( a ). c WB analysis of G3BP1 and AEP in U2OS and 143B with NC or AEP-knockdown (KD) exposed to different chemotherapeutic drugs for 6 h. The arrows point out the truncated fragments of G3BP1 cleaved by AEP. d In vitro cleavage experiment of AEP and G3BP1 (WT and point mutants) purified recombinant proteins. Data are expressed as mean ± SD. *** P < 0.001, **** P < 0. 0001. Comparisons were conducted using one-way ANOVA

Article Snippet: Stable cell lines of U2OS, 143B, and U87-MG were seeded in 96-well cell culture plates and treated with cisplatin (50 μmol/L) or appropriate vehicle solution for 6 h. OCR Fluorometric Assay Kit (Cat# E-BC-F068, Elabscience, Wuhan, China) was used according to manufacturer’s protocol.

Techniques: Knockdown, In Vitro, Purification, Recombinant

Journal: Bone Research

Article Title: Chemotherapeutic drug-triggered AEP-cleaved G3BP1 orchestrates stress granules/nucleoli/mitochondria in osteosarcoma

doi: 10.1038/s41413-025-00453-w

Figure Lengend Snippet: tG3BP1-Ns competitively bind to full-length G3BP1 and negatively modulate SG. a Representative images of SGs in U2OS cells with or without AEP-KD exposed to cisplatin (50 μmol/L), doxorubicin (50 μmol/L) for 6 h. Scale bar = 10 μm. b Quantification of the SG counts per cell ( n = 50) and SG + cell ratio ( n = 6) in cells of ( a ). c Representative images of G3BP1-FL colocalized with tG3BP1-Ns or tG3BP1-Cs in Hela cells. Scale bar = 5 μm. d Co-IP and WB assays of mCherry-tagged tG3BP1-Ns or Cs cotransfected with flag-tagged full-length G3BP1 in HEK293T. e Representative images of SGs in tG3BP1-Ns overexpressed U2OS cells exposed to cisplatin (5 μmol/L), doxorubicin (5 μmol/L) for 6 h. Scale bar = 10 μm. f Quantification of SG counts per cell ( n = 50) and SG + cell ratio ( n = 6) of ( e ). Data are expressed as mean ± SD. * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.000 1. ns no significance. One-way ANOVA

Article Snippet: Stable cell lines of U2OS, 143B, and U87-MG were seeded in 96-well cell culture plates and treated with cisplatin (50 μmol/L) or appropriate vehicle solution for 6 h. OCR Fluorometric Assay Kit (Cat# E-BC-F068, Elabscience, Wuhan, China) was used according to manufacturer’s protocol.

Techniques: Co-Immunoprecipitation Assay

Journal: Bone Research

Article Title: Chemotherapeutic drug-triggered AEP-cleaved G3BP1 orchestrates stress granules/nucleoli/mitochondria in osteosarcoma

doi: 10.1038/s41413-025-00453-w

Figure Lengend Snippet: tG3BP1-Cs translocate into the nucleolus and sequester mRNAs of ribosomal proteins in the nucleolus to inhibit cellular translation. a Representative images of the sub-nucleolar localization of tG3BP1-Cs and sub-nucleolar markers in Hela cells. Scale bar = 5 μm. b Representative images of FISH and IF assays present the nucleolar colocalization of tG3BP1-Cs with FAM-conjugated probes of ribosomal mRNAs, RPS4X, RPL11, and RP27A. c SUnSET experiments analyzed the protein synthesis in U2OS, 143B, and U87-MG cells treated with cisplatin (50 μmol/L) or vehicle for 6 h. d Quantification of protein synthesis of the aforementioned cell lines exposed to cisplatin (50 μmol/L) or vehicle for 6 h were detected with the Click-iT HPG system ( n = 3). Data are expressed as mean ± SD. ** P < 0.01, **** P < 0.000 1. ns no significance. One-way ANOVA

Article Snippet: Stable cell lines of U2OS, 143B, and U87-MG were seeded in 96-well cell culture plates and treated with cisplatin (50 μmol/L) or appropriate vehicle solution for 6 h. OCR Fluorometric Assay Kit (Cat# E-BC-F068, Elabscience, Wuhan, China) was used according to manufacturer’s protocol.

Techniques:

Journal: Bone Research

Article Title: Chemotherapeutic drug-triggered AEP-cleaved G3BP1 orchestrates stress granules/nucleoli/mitochondria in osteosarcoma

doi: 10.1038/s41413-025-00453-w

Figure Lengend Snippet: tG3BP1-Cs bind to mitochondrial mRNA targets and suppress their translation to alleviate mitochondrial stress. a Representative images of the colocalization of tG3BP1-Cs with the mitochondrial marker TOMM20 in Hela cells. Scale bar = 10 μm. b RNP-IP analysis of the mRNA target encoding ribosomal proteins and oxidative phosphorylation binding to tG3BP1-Cs ( n = 3) in tG3BP1-Cs overexpressed U2OS cells. c Ribosome profiling-qPCR analysis demonstrated that tG3BP1 overexpression in U2OS cells significantly downregulates mitochondrial genes translation. d WB analysis of mitochondrial genes expression in cell lines exposed to cisplatin (50 μmol/L) or vehicle for 6 h. e Cisplatin-induced mitochondrial damage was detected by JC-1 probe staining in cells of ( d ). Data are expressed as mean ± SD. *** P < 0.001, **** P < 0.000 1. One-way ANOVA

Article Snippet: Stable cell lines of U2OS, 143B, and U87-MG were seeded in 96-well cell culture plates and treated with cisplatin (50 μmol/L) or appropriate vehicle solution for 6 h. OCR Fluorometric Assay Kit (Cat# E-BC-F068, Elabscience, Wuhan, China) was used according to manufacturer’s protocol.

Techniques: Marker, Phospho-proteomics, Binding Assay, Over Expression, Expressing, Staining

Journal: bioRxiv

Article Title: SFPQ Promotes Homologous Recombination via mRNA Stabilization of RAD51 and Its Paralogs

doi: 10.1101/2025.09.08.674956

Figure Lengend Snippet: (A) Representative images show DAPI (blue), EdU (green), pATM (magenta), SFPQ (cyan), and merged (right) staining in siNTC-treated DIvA U2OS cells under break and no break conditions. Breaks were induced with 4-hydroxytamoxifen for 24 hours, and images were captured using a 10X magnification. Cells (∼20,000 per well) were imaged across three wells per condition (16 fields per well; 48 images total) and quantified in Cell Profiler for nuclear intensity, foci count, and cell-cycle stage based on EdU/DAPI. Data are representative of n=48 images. (B) Quantification of SFPQ–pATM and pATM–γH2AX co-localization in G2-phase cells. Violin plots show correlation coefficients of SFPQ and pATM (left) and pATM and γH2AX (right) in G2 cells with or without DNA breaks. (C) ChIP-seq data representing SFPQ-bound chromatin at 122 defined AsiSI sites under uncut (noDSB) and cut (+4OHT, 4 hours) conditions (left). ChIP-seq data representing SFPQ bound to RNU sites (right). Immunoprecipitation was performed using SFPQ polyclonal antibody. Normalized ChIP-seq signal was plotted for ±1.5 kb around AsiSI sites. SFPQ occupancy profiles are shown for two independent replicates with DSB induction (dark blue and light blue) and for the noDSB control (yellow).

Article Snippet: U2OS DR-GFP cells (female; provided by Jeremy Stark’s laboratory, City of Hope, Duarte, California, USA) and wild-type U2OS cells (female; ATCC) were both grown in DMEM supplemented with 10% FBS and 1% P/S.

Techniques: Staining, ChIP-sequencing, Immunoprecipitation, Control

Journal: bioRxiv

Article Title: SFPQ Promotes Homologous Recombination via mRNA Stabilization of RAD51 and Its Paralogs

doi: 10.1101/2025.09.08.674956

Figure Lengend Snippet: (A) (Top) SFPQ mean intensity: Violin plots (with embedded boxplots) show the single-cell distribution of nuclear SFPQ mean fluorescence intensity in DIvA U2OS cells under no break (untreated) and break (4-hydroxytamoxifen, 4-OHT) conditions. Each dot is one nucleus; boxplots denote median and interquartile range. Cell-cycle phase (G1, S, G2) was assigned per cell using EdU incorporation (green) and DAPI DNA content (blue). (Bottom) SFPQ foci per cell: Violin plots (with embedded boxplots) show the number of SFPQ nuclear foci per cell under the same conditions and cell-cycle stratification. Quantification: Cells were left untreated or treated with 4-OHT to induce AsiSI-mediated DSBs, then stained for SFPQ (cyan), EdU, and DAPI. Images were analyzed in Cell Profiler to segment nuclei, call SFPQ foci, compute per-nucleus mean intensity and foci counts, and assigned cell-cycle stage from EdU/DAPI features. (B) Non–pre-extracted immunofluorescence staining of pATM and SFPQ in DIvA U2OS cells with or without DSB induction. Cells were left untreated or treated with 4-hydroxytamoxifen (4-OHT) to induce AsiSI-mediated DSBs and stained for DNA (DAPI, blue), EdU incorporation (green), phosphorylated ATM (pATM, magenta), and SFPQ (cyan). Images were acquired without cytoskeletal (CSK) pre-extraction to visualize total nuclear staining patterns. Merged images show nuclear co-localization of pATM and SFPQ signals in the presence and absence of DNA damage.

Article Snippet: U2OS DR-GFP cells (female; provided by Jeremy Stark’s laboratory, City of Hope, Duarte, California, USA) and wild-type U2OS cells (female; ATCC) were both grown in DMEM supplemented with 10% FBS and 1% P/S.

Techniques: Fluorescence, Staining, Immunofluorescence, Extraction

Journal: bioRxiv

Article Title: SFPQ Promotes Homologous Recombination via mRNA Stabilization of RAD51 and Its Paralogs

doi: 10.1101/2025.09.08.674956

Figure Lengend Snippet: (A) mRNA-seq log₂ fold changes of RAD51 paralogs and pooled transcripts in the indicated Gene Ontology (GO) categories in DIvA U2OS cells treated with siSFPQ compared to siNTC control for 72 hours in the absence of DSBs. Data represent the mean of three biological replicates. Individual p-values were adjusted for multiple comparisons. Aggregate p-values were combined by Fisher’s method. (B) Differential transcript utilization analysis for RAD51 paralogs. mRNA-seq data from siNTC versus siSFPQ DIvA U2OS cells were analyzed for transcript isoform usage. Bars represent the likelihood ratio statistic for each gene, with blue bars indicating genes showing significant shifts in transcript utilization (RAD51B, RAD51C) upon SFPQ depletion. Grey bars indicate genes without significant changes. (C) Western blot analysis of SFPQ and RAD51 protein levels of the three biological replicates used for mRNA-seq following siNTC or siSFPQ treatment. Total protein staining is shown as a loading control. (D) Representative images show DAPI (blue), EdU (green), RAD51 (magenta), SFPQ (cyan), and merged (right) staining in siNTC-treated DIvA U2OS cells under break and no break conditions, pre-extracted with CSK. Breaks were induced with 4-OHT for 4 hours. Cells (∼20,000 per well) were imaged across four wells per condition (16 fields per well; 64 images total) and quantified in Cell Profiler for nuclear intensity, foci count, and cell-cycle stage based on EdU/DAPI. (E) Quantification of SFPQ and RAD51 foci per cell in DIvA U2OS cells following siRNA treatment and DNA damage induction. Violin plots show the distribution of foci counts across conditions with or without 4-hydroxytamoxifen (4-OHT) treatment and following transfection with non-targeting control (NTC), RAD51-targeting, or SFPQ-targeting siRNAs. Data are representative of n=64 images. (F) Violin plots showing correlation coefficients of SFPQ and RAD51 in G2 cells with or without DNA breaks. Quantification of SFPQ-RAD51 foci co-localization in G2-phase cells was performed using Cell Profiler analysis of single-cell fluorescence signals.

Article Snippet: U2OS DR-GFP cells (female; provided by Jeremy Stark’s laboratory, City of Hope, Duarte, California, USA) and wild-type U2OS cells (female; ATCC) were both grown in DMEM supplemented with 10% FBS and 1% P/S.

Techniques: Control, Western Blot, Staining, Transfection, Fluorescence

Journal: bioRxiv

Article Title: SFPQ Promotes Homologous Recombination via mRNA Stabilization of RAD51 and Its Paralogs

doi: 10.1101/2025.09.08.674956

Figure Lengend Snippet: (A) Differential expression analysis of mRNA-seq data comparing DSB versus no-DSB conditions in siNTC-treated DIvA U2OS cells (n=3 biological replicates). Mean log₂ fold change for the same targets is shown as . No significant expression differences were detected for these targets upon DSB induction in control cells. (B) ChIP-seq data showing SFPQ abundance at sites upstream and downstream of RAD51-paralog genes both without (noDSB) or with (+DSB) 4 hours of DSB induction. Data displayed is the average signal across all 6 RAD51 paralogs. (C) mRNA-seq log₂ fold changes of transcript expression of the indicated gene or GO category in DIvA U2OS cells treated with siSFPQ compared to siNTC control for 72 hours in the absence of DSBs. Data represent the mean of three biological replicates. Individual p-values were adjusted for multiple comparisons. Aggregate p-values were combined by Fisher’s method. (D) Western blot of DIvA U2OS cells treated with siSFPQ with or without p53 inhibition by PFT-α (30 µM) for 24 hours. Lysates were blotted for SFPQ, HSP70, MDM2 and RAD51. (E) (Left) Western blot of p53-null K562 cells treated with siSFPQ. Total protein staining is shown as a loading control. (Right) Quantification of SFPQ and RAD51 normalized band intensities relative to total protein is graphed.

Article Snippet: U2OS DR-GFP cells (female; provided by Jeremy Stark’s laboratory, City of Hope, Duarte, California, USA) and wild-type U2OS cells (female; ATCC) were both grown in DMEM supplemented with 10% FBS and 1% P/S.

Techniques: Quantitative Proteomics, Expressing, Control, ChIP-sequencing, Western Blot, Inhibition, Staining

Journal: bioRxiv

Article Title: SFPQ Promotes Homologous Recombination via mRNA Stabilization of RAD51 and Its Paralogs

doi: 10.1101/2025.09.08.674956

Figure Lengend Snippet: (A) Cycloheximide (CHX) ± carfilzomib (Carf) protein stability assay in DIvA U2OS cells. Cells were transfected with either non-targeting control (siNTC) or SFPQ-targeting (siSFPQ) siRNAs for 72 h, then treated with CHX alone or CHX + Carf to inhibit protein synthesis and proteasomal degradation, respectively. Lysates were collected at 0-, 2-, and 4-hours post-drug treatment from three independent biological replicates. (B) RAD51 abundance from normalized to total protein and then to 0 hr. condition. Data points represent individual replicates; lines indicate the mean. (C) RIP-seq analysis of SFPQ binding across RAD51 family paralogs in melanoma cells. Read coverage tracks show SFPQ-associated RNA fragments aligned to the genomic loci of RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3. Peaks indicate regions of enriched SFPQ binding, with annotations of exon–intron structure shown below each track. Model for SFPQ-mediated stabilization of RAD51 mRNA and its impact on homologous recombination (HR). In the presence of SFPQ, the protein binds to RAD51 mRNA, promoting transcript stabilization. Stable RAD51 mRNA ensures sufficient RAD51 protein production, enabling efficient RAD51 filament formation on DNA and supporting robust HR (left). Upon SFPQ loss, RAD51 family mRNAs are destabilized, leading to reduced RAD51 protein abundance. This reduction impairs HR efficiency (right).

Article Snippet: U2OS DR-GFP cells (female; provided by Jeremy Stark’s laboratory, City of Hope, Duarte, California, USA) and wild-type U2OS cells (female; ATCC) were both grown in DMEM supplemented with 10% FBS and 1% P/S.

Techniques: Stability Assay, Transfection, Control, Binding Assay, Homologous Recombination, Quantitative Proteomics