Journal: bioRxiv

Article Title: Engineering a pacemaker-driven human mini-heart guided by spatial and single cell multi-omics of sinoatrial node development

doi: 10.64898/2026.05.07.723626

Figure Lengend Snippet: a, Schematic of zebrafish drug treatment experiments. b, Representative bright-field images of zebrafish larvae at 54 hpf. Scale bar=100 µm. c, Representative fluorescence images of zebrafish /larvae at 54 hpf treated with 5 µM Afatinib, 5 uM BAY-593 (YAPi) or vehicle control. Scale bar=100 µm. d, e, Quantification of the number of ISL1/2 + cells (c) and ISL1/2 + area in zebrafish larvae treated with 5 uM Afatinib, 5 uM BAY-593 or vehicle control. Data are shown as mean ± SEM; *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. For each experiment, N = 25 larvae. For each drug-treated set there was a consistent loss of Isl1-staining; 3 larvae from each set were randomly chosen for quantification, carried out by a blinded investigator.

Article Snippet: At 54 hpf larvae were fixed in 2% PFA for 2 hours at room temperature, washed extensively in PBS with 0.3% TritonX-100 (PBX), incubated in blocking buffer (BB: PBX, 0.5% BSA, 10% goat serum) for 2 hours at room temperature, incubated overnight at 4°C in BB containing 1/50 dilution of mouse anti-ISL1/2 antibody (Iowa Developmental Studies Hybridoma Bank #39.4D5), washed extensively with PBX, incubated at room temperature for 2 hours in BB with a 1/200 dilution of goat anti-mouse IgG2b Alexa Fluor568 (Invitrogen #A-21144), washed extensively with PBX, and mounted in 1:1 PBS:glycerol for imaging on a Zeiss LSM800 confocal microscope.

Techniques: Fluorescence, Control, Staining