Fig. 2: The asymmetric NP pool gives rise to asymmetric lineages.
From: Microtubule polarity determines the lineage of embryonic neural precursor in zebrafish spinal cord
a Scheme of NP daughter photoconversion assay. After measurement of spindle-MT enrichment (GFP-DCX, yellow) in a single dividing NP (24hpf), pSMOrange was photoconverted (from red to far-red; green color). After 48 h, the composition of the lineage and the type of division pattern (n•n, p•p and n•p) of the photoconverted cell (here green) and the non-photoconverted cell (here magenta) were determined. b Maximal z-projection of a dividing 24hpf NP showing spindle-MTs (GFP-DCX, yellow) and pSMOrange (magenta /green; green is photoconverted). c Three maximal z-projections of the different lineages found 48 h after photoconversion. Lineages are assessed according to the resulting number of cells: 2 cells for n•n, 2 + 1 cells for n•p, and 2 + 2 cells for p•p. This assay allows to quantify the spindle-MT asymmetry in the mother NP and to trace independently the lineage of its two initial daughter cells after photoconversion. b, c Scale bars, 5 μm. d Percentage of asymmetric NPs (according to spindle-MT enrichment) for all photoconverted NPs (n = 32), NP which generated asymmetric lineages (n•p, n = 15) or symmetric lineages (n•n + p•p, n = 17), respectively. Chi-square test indicates that the asymmetry of MTs in the mother NP is statistically predictive of the type of subsequent lineage. 95% confidence; *p < 0.05 and **p < 0.01. Non indicated comparison, non-significant.
