Post-Embryonic Nerve-Associated Precursors to Adult Pigment Cells: Genetic Requirements and Dynamics of Morphogenesis and Differentiation
(A) Occurrence of cells in sections from the mid-trunk of wild-type and erbb3b mutant larvae. Each class of cells was reduced in erbb3b mutants (all P<0.0001). (B,C) Cell frequencies in wild-type and erbb3b mutants across stages. pre-met, pre-metamorphosis (4.9–5.3 SSL); early met, early metamorphosis (6.2–8.0 SSL); late met, late metamorphosis (9.0–13.0 SSL). (B) The frequency of foxd3+; mitfa::GFP+ cells was greatest in wild-type larvae during early pigment pattern metamorphosis (doubly vs. singly labeled cells, difference among stages: χ2 = 15.7, d.f. = 2, P<0.0005; N = 1217 total cells examined). Doubly labeled cells tended to be rarer and delayed in erbb3b mutants (N = 83 total cells examined). (C) The frequencies of EdU+ cells differed significantly among stages, with more foxd3+ and sox10+ cells labeled with EdU during the pre-metamorphic period, and more mitfa::GFP+ cells labeled with EdU during early metamorphosis (EdU labeling frequency variation among stages, foxd3+: χ2 = 11.3, d.f. = 2, P<0.005, N = 450 cells; sox10+: χ2 = 140.7, d.f. = 2, P<0.0001; N = 1679 cells; mitfa::GFP+: χ2 = 14.4, d.f. = 2, P<0.001, N = 927 cells). In erbb3b mutants, EdU labeling frequencies were reduced in comparison to wild-type for foxd3+ cells (χ2 = 3.4, d.f. = 1, P = 0.06; N = 44 cells) and sox10+ cells (χ2 = 11.4, d.f. = 1, P<0.001; N = 77 cells), though not significantly so for mitfa::GFP+ cells (P>0.1; N = 59 cells). Asymmetric confidence intervals in B and C, Bayesian 95% upper and lower bounds.