Fig. 2

CDK13 interacts with E2F5 in PCa cells. a, Co-immunoprecipitation coupled with mass spectrometry (CoIP-MS) was performed with an anti-CDK13 in PC3 cells to detect the proteins interacting with CDK13, which are shown on the right panel. b, Heat map showing the differential expression (fold changes) of mRNAs between PCa and BPH tissues. Red color indicates several genes that are known to be transcriptionally upregulated in PCa tissues. c, CoIP analysis was used to detect the interaction between CDK13 and E2F5, and β-actin was used as a negative control. d, in situ proximity ligation (PLA) analysis detected the interaction between CDK13 and E2F5. Red color indicates PLA-positive cells. e, Immunofluorescence staining was performed to detect the expression and location of CDK13 and E2F5 in PCa and BPH tissues. Scale bars = 100 μm. f, E2F5 mRNA level was determined by RT-qPCR in 30 pairs of PCa and normal prostate tissues. **P < 0.01 vs. normal tissues. g, The expression levels of E2F5 mRNA in BPH and PCa tissues from the GSE13507 database (P < 0.0001). h, E2F5 protein expression was detected by Western blotting in 3 pairs of randomly selected BPH (B) and PCa (P) tissues. i, Immunohistochemistry staining detected the E2F5 protein expression in PCa and BPH tissues. j and k, the correlation between CDK13 and E2F5 mRNA expression in the PCa tissues was analyzed by Pearson correlation analysis in our clinical data (R = 0.4928, P = 0.0049) or several other data published in TCGA database (Yu: R = 0.3959, P = 0.0001; Wallace: R = 0.3752, P = 0.0015; Glinsky: R = 0.238, P = 0.0347)