Fig. s5

Cell transplants support a model in which jam3b functions autonomously to melanophores. (A) Wild-type cells that developed as melanophores formed a wild-type pattern when transplanted to mutant hosts that lack melanophore owing to a null allele of mitfa, which normally acts within the melanophore lineage (Eom et al., 2012; Lister et al., 1999; Parichy and Turner, 2003a). By contrast, jam3b mutant cells that developed as melanophores in this background retained patterns and morphologies typical of jam3b mutants (n=4 chimeras that developed jam3b donor melanophores). The same phenotypes were evident in transplants of jam3b mutant cells to albino mutant hosts, which develop melanophores that lack melanin (n=6 chimeras that developed jam3b mutant melanophores). (B) When iridophores wild-type for jam3b developed in a jam3b mutant background, host melanophores retained a mutant arrangement and appearance evident in brightfield (arrowheads, upper). In these experiments, donor cells were transplanted from embryos mutant for temperature-sensitive allele mitfa^vc7, and chimeras reared at restrictive temperature (32 °C), at which melanophores do not develop (Gur et al., 2020; Johnson et al., 2011; Zeng et al., 2015). Donors iridophores were marked by pnp4a:mem-mCherry expression (middle; merge with brightfield, lower) and images shown are stiched computationally from multiple image tiles. In both A and B other donor cell types may be present as well, though pigment cells rarely develop in close association with mesodermal or ectodermal derivatives in such transplants [e.g., Fig. 4; (Budi et al., 2008; Eom et al., 2012; Parichy and Turner, 2003a; Parichy et al., 2003). Scale bars, 500 μM.