Journal: mBio
Article Title: EBNA1 SUMOylation by PIAS1 suppresses EBV lytic replication and enhances episome maintenance
doi: 10.1128/mbio.02639-25
Figure Lengend Snippet: PIAS1 enhances EBNA1 SUMOylation both in vivo and in vitro . ( A ) HEK-293T cells were transfected with plasmids encoding Halo-V5-EBNA1, Halo-PIAS1, and His-SUMO2. Whole-cell lysates (input) were analyzed by WB using antibodies against SUMO2/3, PIAS1, V5, and β-actin. SUMOylated proteins are indicated by brackets. EBNA1 was immunoprecipitated using anti-V5 magnetic beads, followed by WB analysis with antibodies as indicated. Arrows denote SUMOylated EBNA1. ( B ) In vitro SUMOylation assay was conducted using a combination of purified proteins, including E1, E2, SUMO2, PIAS1, and the substrate V5-EBNA1, as specified. The reaction was stopped by adding 2× SDS-PAGE loading buffer, followed by WB analysis using anti-V5-HRP antibody. SUMOylated EBNA1 is indicated by brackets. ( C ) WB analysis of PIAS1 and β-actin expression in non-targeting control (NC) and PIAS1-depleted (sg-PIAS1) Akata (EBV+) cells. ( D ) Control (NC) and PIAS1-depleted (sg-PIAS1) Akata (EBV+) cells were blocked with 3% bovine serum albumin (BSA) in phosphate-buffered saline (PBS) for 1 h at room temperature, followed by incubation with mouse anti-EBNA1 and rabbit anti-SUMO2/3 antibodies. PLA probes were subsequently added for ligation and amplification. Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI) and visualized using a Nikon AXR confocal microscope. The close proximity between EBNA1 and SUMO2/3 is indicated by red fluorescent PLA signals.
Article Snippet: Briefly, cells were blocked with 3% bovine serum albumin (BSA) in phosphate-buffered saline (PBS) at room temperature for 1 h, then incubated with PBS control or a mixture of mouse anti-EBNA1 (Cat. #sc-81581, Santa Cruz) and rabbit anti-PIAS1 (Cat. #ab77231, Abcam) or rabbit anti-SUMO2/3 (Cat. # 11251-1-AP, Proteintech) antibodies (1:50 dilution in 3% BSA) at 4°C overnight.
Techniques: In Vivo, In Vitro, Transfection, Immunoprecipitation, Magnetic Beads, Purification, SDS Page, Expressing, Control, Saline, Incubation, Ligation, Amplification, Staining, Microscopy