Fig. 3

Tubercidin induces aggregation and enlargement of SC35-labeled nuclear speckles (NSs) in mouse cardiomyocytes. A Confocal microscopy images showing SC35-labeled NSs in FMC84 cardiomyocytes after 6 h of Tubercidin treatment. Merged images highlight the colocalization of SC35 (green) with DAPI-stained nuclei (blue). Tubercidin treatment led to a decrease in the number of SC35-labeled NSs and an increase in their size compared to control cells under serum starvation and/or hypoxia. B Confocal microscopy images showing SC35-labeled NSs in HL-1 cardiomyocytes after 6 h of Tubercidin treatment. Similar to FMC84 cells, Tubercidin treatment resulted in fewer but larger SC35-labeled NSs compared to control cells under serum starvation and/or hypoxia. Bar, 10 μm. C Quantitative analysis of the number of SC35-labeled NSs condensates in FMC84 cells and (D) HL-1 cells treated with Tubercidin for 6 h. The number of NSs significantly decreased and the size of NSs, with more condensates falling into larger size categories (1.5–2 μm) in FMC84 cells and HL-1 cells exposed to Tubercidin compared to controls under serum starvation and/or hypoxia