Journal: PLOS Biology
Article Title: Casein kinase 2-mediated phosphorylation of the splicing factor SF3B3 plays a key role in esophageal squamous cell carcinoma progression
doi: 10.1371/journal.pbio.3003729
Figure Lengend Snippet: (A) KYSE140 cells transfected with siCTL or two independent siSF3B3 (siSF3B3-1 and siSF3B3-2) were subjected to RT-qPCR analysis to assess mRNA expression levels of SF3B3 (mean ± SD; *** P < 0.001, Student t test). (B) RNA extracted from cells as described in (A) were subjected to library preparation and Nanopore sequencing, and the number of alternative splicing (AS) events regulated by SF3B3 is shown (|ΔPSI| ≥ 0.2 and FDR ≤ 0.05). Cassette Exons or Exon Skipping (ES); Intron Retain (IR); Alternative 5′ Splice Site (5′ ASS); Alternative 3′ Splice Site (3′ ASS). (C) The number of exon inclusion and skipping induced by SF3B3 is shown by pie chart. (D) The Pearson’s correlation was analyzed between the expression levels of SF3B3 and genes containing SF3B3-regulated cassette exons that are highly expressed in ESCC (Log 2 FC ≥ 2, P ≤ 0.01). Red dots indicate genes with r ≥ 0.3. (E) GO analysis results for genes with SF3B3-regulated cassette exons. The top 6 most enriched GO terms are shown. (F) Kaplan–Meier analyses of progression-free interval in ESCC patients using EXOSC2 cassette exon 4 as an input in the OncoSplicing dataset. (G) KYSE140 cells transfected with siCTL, siSF3B3-1, or siSF3B3-2 were subjected to standard PCR analysis to examine the expression of both the short and long isoforms of EXOSC2 as indicated at the bottom. Percentage spliced in (PSI) values were measured by Image J. The position of the cassette exon in EXOSC2 is as follows: EXOSC2 ( NM_001114122 , exon 4). DNA marker is indicated on the left. (H) KYSE140 cells were transfected with siCTL or siSF3B3 in the presence or absence of control vector, SF3B3 (WT), or SF3B3 (T1200A), followed by standard PCR analysis to examine the short and long isoforms of EXOSC2 as described in (G). (I) KYSE140 cells treated with or without CX-4945 (10 μM) were subjected to standard PCR analysis to examine the short and long isoforms of EXOSC2 as described in (G). (J) HEK293T cells transfected with GFP control vector or GFP-tagged SF3B3 (WT), SF3B3 (T1200A), or SF3B3 (T1200D) were subjected to IP analysis with anti-GFP magnetic beads, followed by IB analysis with antibodies as indicated. (K) HEK293T cells transfected with GFP control vector or GFP-tagged SF3B3 (WT), SF3B3 (T1200A), or SF3B3 (T1200D) were subjected to RIP analysis with anti-GFP magnetic beads, followed by RT-qPCR analysis to examine the binding of SF3B3 protein with genes as indicated (mean ± SD; *** P < 0.001, ** P < 0.01, Student t test) . (L–N) KYSE140 cells s t ably expressing control lentiviral vector, EXOSC2 long isoform (EXOSC2-L), or EXOSC2 short isoform (EXOSC2-S) were subjected to IB analysis (L), cell proliferation assay (M), and colony formation assay (N) (mean ± SD; ns: not significant, *** P < 0.001, Student t test). (O) The quantifica t ion of the crystal violet dye in (N) is shown (mean ± SD; ns: not significant, ** P < 0.01, *** P < 0.001, Student t test). (P–R) KYSE140 cells transfected with siCTL or siSF3B3, followed by infec t ion with lentivirus expressing control vector, EXOSC2-L, or EXOSC2-S were subjected to IB analysis (P), cell proliferation assay (Q), and colony formation assay (R) (mean ± SD; * P < 0.05, ** P < 0.01, Student t test). (S) The quantification of the number of colonies in (R) (mean ± SD; *** P < 0.001, Student t test). (T) KYSE140 cells infected with lentivirus expressing shCTL or shSF3B3 in the presence or absence of lentivirus expressing control vec t or, EXOSC2-L, or EXOSC2-S were injected into BALB/c nude mice for 4 weeks, and the tumors were collected and photographed. (U, V) The tumor volume (U) and weight (V) as shown in (T) (mean ± SD; * P < 0.05, ** P < 0.01, *** P < 0.001, Student t test). (W) The expression of the short and long isoforms of EXOSC2 were measured by standard PCR as described in (G) in paired ESCC and adjacent normal tissues ( n = 6). (X) The quantification of the PSI values in (W) (mean ± SD; * P < 0.05, Student t test). The data underlying the graphs shown can be found in .
Article Snippet: The proteasome inhibitor MG-132 (T2154), the CK2 inhibitor CX-4945 (T2259), and the USP7 inhibitor P5091 (T6925) were purchased from TargetMol.
Techniques: Transfection, Quantitative RT-PCR, Expressing, Nanopore Sequencing, Alternative Splicing, Marker, Control, Plasmid Preparation, Magnetic Beads, Binding Assay, Proliferation Assay, Colony Assay, Infection, Injection