Fig. 5: Lefty is needed to slow the spread of Nodal.

a Comparison of Nodal mRNA expression and pSmad2/3 over time in gastruloids created with WT and Lefty1/2 compound KO hESCs. Representative images at all time points are shown, scale bar, 100 µm. b Quantification of 6 colonies with indicated genotypes at each time point, data are presented as mean values + /− SEM. c Analysis of Wnt signaling. Transcripts of Axin2, a Wnt signaling transcriptional target, and transcripts of Lefty1/2 in gastruloids at 20 h and 30 h were co-examined via smFISH. Mean intensity of FISH signal was quantified as function of distance from colony center. Data are presented as mean values + /− SEM, n = 6 biological replicates. Scale bar, 100 µm. d Analysis of the BMP signal transducers pSmad1/5/8 and the BMP target HAND1 in 2D gastruloids at 42 h. Mean intensity is quantified as a function of distance from colony center. Data are presented as mean values + /− SEM, n = 6 biological replicates. Scale bar, 100 µm.