Rabbit anti p21

Mice were anesthetized and perfused with PBS. The kidneys were collected, fixed with 4% PFA, and cut to obtain 30 ​μm sections using a vibratome (Invitrogen, U.S.A). After three rinses in PBS (5 ​min each), the sections were blocked in PBST (PBS ​+ ​0.3% Triton X-100) with 3% BSA for 2 ​h, and were then incubated in primary antibodies rabbit anti-lamin B1 (Abclonal, China), mouse anti-p53 (Abcam, UK) or rabbit anti-p21 (ABclonal, China) with a dilution of 1:1000 ​at 4 ​°C for 24 ​h, followed by three rinses in PBS. Then, the sections were incubated with goat anti-rabbit IgG H&L Alexa Fluor® 488 (1:300, Abcam, UK) or goat anti-mouse IgG H&L Alexa Fluor® 488 secondary antibodies (1:300, Abcam, UK) for 2 ​h at room temperature. After the incubation, the sections were washed with PBS for 5 ​min, and the nuclei were counterstained with DAPI for 5 ​min. Finally, the sections were washed in PBST and mounted in mounting medium. Fluorescence images were acquired with a 20 ​× ​objective on a confocal microscope.
Flies were anesthetized with CO₂, dissected in PBS, and fixed with 4% PFA at room temperature. Brain sections were prepared and incubated with rabbit anti-caspase-3 primary antibody (1:500, Beyotime, China) and then with goat anti-rabbit IgG H&L Alexa Fluor® 488 (1:200, Abcam, UK), followed by DAPI staining and fluorescence imaging.

293 ​T cells (1.0 ​× ​10⁶) were collected and total protein was extracted with RIPA (Radioimmunoprecipitation) lysis buffer (Beyotime, China). The protein lysates were then separated by SDS-PAGE and transferred to nitrocellulose filter membranes. The membranes were incubated with primary antibodies rabbit anti-p21 (1:1000, ABclonal, China), rabbit anti-lamin B1(1:1000, Abcam, UK), rabbit anti-decoy receptor 2 (DcR2) (1:1000, Proteintech, U.S.A), or mouse anti-glyceraldehyde 3-phosphate dehydrogenase (GAPDH) (1:10,000, ABclonal, China) and then with goat anti-rabbit IgG (H ​+ ​L) DyLight™ 800-Labeled or goat anti-mouse IgG (H ​+ ​L) DyLight™ 680-Labeled secondary antibodies (1:10,000, KPL, U.S.A). The immune-positive bands were visualized using an Odyssey scanner (LI-COR Biosciences, USA). The band densities of p21, lamin B1, and DcR2 were quantified in ImageJ and normalized against those of GAPDH, representing their protein expression levels respectively.