Figure 2. Lineage tracing by photoconversion demonstrates neural crest origin of microvillous neurons.
(A) Nuclear Dendra2 (low level green) was photoconverted in Sox10:eGFP+ (bright green) neural crest cells at 14–16 hpf (10–14 somite stage) in live embryos. (B)–(C') Representative example z-planes show unilateral photoconversion of a few cells (B and B') or a large number of cells (C and C'). (B and C) show ubiquitous Dendra2 (low level green) and Sox10:eGFP (bright green), and (B' and C') show photoconverted Dendra2 (red). (D) Photoconverted cells are visible in the contralateral nasal cavity at 29 hpf; (E and E') show a 2.5-μm-thick z-plane slice of the boxed area with photoconverted cells (red, arrowheads). (F and F') At 55 hpf, photoconversion of a small number of cells (B and B') results in a subset of Sox10:eGFP+ microvillous neurons being labeled by photoconverted Dendra2 on the contralateral side. (G and G') Large-scale photoconversion (C and C') labels most Sox10:eGFP+ microvillous neurons. Directly adjacent ciliated neurons are never labeled. (F–G') z = 2.5 μm; Sox10:eGFP: green; Dendra2Green: blue; Dendra2Red: red; histology in brightfield. Orientation arrows: A: anterior; P: posterior; D: dorsal; V: ventral; L: lateral. Scale bars: 50 μm (A); 20 μm (B–D); 10 μm (F–G'). See also Figure 2—figure supplement 1.
Figure 2—figure supplement 1. Shown are a few 55 hpf microvillous neurons that are Sox10:eGFP negative (arrowheads) and were not photoconverted, suggesting a possible non-neural crest origin.
