Preferential contribution of dusp6:dGFP+ cells to pouches
(A-E) Representative sections from a time-lapse recording of a wild-type dusp6:dGFP; her5:mCherryCAAX embryo (see Movie S2) in which individual cells were tracked (colored dots). Orange and blue arrows show two cells that were dusp6: dGFP- in the posterior-most domain of pharyngeal endoderm at the start of the recording (T0) and then turned on dusp6:dGFP and contributed to the sixth pouch (p6) over the next 8 hours. White and red arrowheads show two adjacent cells that never turned on dusp6:dGFP and were excluded from the pouch. (F) Quantification of the contribution of cells to the pouches based on whether they were initially dusp6:dGFP- (left bar) or dusp6:dGFP+ (right bar). For initially dusp6:dGFP- cells, we then quantified the number of cells that stayed GFP- or turned on dusp6:dGFP (GFP+). For initially dusp6:dGFP+ cells, we quantified the number of cells that maintained dusp6: dGFP (GFP+) or extinguished GFP (GFP-). For both, we also scored the contribution of each category to pouches. Both cells that turned on dusp6:dGFP (p<0.001) and maintained dusp6:dGFP (p=0.002) contributed to pouches at a high frequency than cells that remained or turned off dusp6:dGFP. y-axis represents % of cells of each category. (G-I) High magnification confocal sections show her5:mCherryCAAX labeling of endodermal cell membranes within the fourth pouch (p4) and presumptive fifth pouch (p5) at 28 hpf. The epithelium of nascent pouch p5 was multilayered in 8/8 wild-type siblings and 5/5 fgf8a mutants but only in 1/4 wnt11r mutants. Instead, pre-pouch cells in 3/4 wnt11r mutants retained a columnar epithelial morphology. Scale bars represent 20 μM.
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