Fig 2: LCR sequences are critical for CPSF6 interaction with HIV-1 cores in infected cells.a PLAs showing association of HA-tagged ectopically expressed WT and chimeric CPSF6 proteins with incoming HIV-1 particles in HEK293T CKO cells. The cells were fixed at 6 hpi and PLAs were performed using anti-HA (ab236632, Abcam) and anti-HIV-1 CA specific antibodies (ARP-4121, NIH AIDS Reagent Program). The representative images show PLA puncta (red) and nuclei stained with DAPI (blue). Scale bar is 2 µm. b Quantitative results showing numbers of PLA puncta per cell by analyzing twenty-five cells for each sample. The averaged data (+/- SD) from three independent experiments are shown. Statistical significance of comparison of WT versus the chimeric CPSF6 proteins was determined by Student’s two-sample, two-tailed t-test. CPSF6/AD: p = 3.1E-12; CPSF6/NE: p = 2.4e-12; CPSF6/FU: p = 0.54; CPSF6/CD: p = 0.26; CKO: p = 8.8E-13. P > 0.05 was considered not significant (ns) and p < 0.0001 was considered highly significant (***). Source data are provided as a Source Data file. AD ADD2, NE NEURM, FU FUS, CD CDK19, WT wild-type CPSF6, CKO CPSF6 knock-out, LCR low complexity region.

Fig 3: CPSF6 is upregulated and predicts poor prognosis in HCC. a IHC staining of CPSF6 in surrounding non-tumor and HCC tissues. Percentage of CPSF6 IHC was shown in bar graph. Scale bar, 50 µm. b Western blot assay for detecting CPSF6 expression in 16 paired surrounding non-tumor (N) and HCC tumor (T) tissues. ß-actin was used as internal control. c qRT-PCR analysis of CPSF6 mRNA in 36 paired surrounding non-tumor (N) and HCC tumor (T) tissues. GAPDH was used as internal control. d, e Kaplan–Meier analysis of the correlation of CPSF6 protein expression with OS (d) and DFS (e). The expression level of CPSF6 protein was detected by immunohistochemistry. f qRT-PCR analysis of CPSF6 mRNA in TCGA liver cancer samples. g,h Kaplan–Meier analysis of OS (g) and DFS (h) data from TCGA liver cancer data containing 364 patients. The data of g and f can be obtained through online website (http://kmplot.com/analysis/).**p < 0.001, Student’s t-test

Fig 4: Virus infection of HEK293T cells. (A) Western immunoblots using anti-LEDGF/p75 and anti-CPSF6 antibodies; ß-actin was blotted as a loading control. Numbers to the left are mass marker positions in kDa. (B) Infectivities of indicated GFP reporter viruses with WT, LKO, CKO, and DKO cells. (C) Left, infectivities of Luc reporter viruses in relative light units per µg total protein (RLU/µg). To highlight differences among cell types, the data were replotted by normalizing each virus with WT cells to 100% (rightward graph). Results (average ± standard deviation [SD]) compile data from at least four independent experiments, with each experiment conducted in duplicate. Significant differences in comparison to results observed with WT cells are indicated: *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.

Fig 5: Interference with CPSF6 promotes apoptosis of hepatocellular carcinoma cells. A CPSF6 mRNA expression in Huh-7 cells transfected with sh-CPSF6-1/2 was detected by RT-qPCR analysis. B CPSF6 protein expression in Huh-7 cells transfected with sh-CPSF6-1/2 was determined by Western blot analysis. *P < 0.05 and ***P < 0.001 vs. Control group. ###P < 0.001 vs. sh-NC group. $P < 0.05 vs. sh-CPSF6-1 group. C The viability of Huh-7 cells transfected with sh-CPSF6-2 was analyzed by MTT assay. D The apoptosis of Huh-7 cells transfected with sh-CPSF6-2 was detected by TUNEL assay. E The expression of apoptosis-related proteins in Huh-7 cells transfected with sh-CPSF6-2 was analyzed by Western blot analysis. **P < 0.01 and ***P < 0.001 vs. Control group. ##P < 0.01 and ###P < 0.001 vs. sh-NC group. N = 3