Fig. 4

Qualitative evaluation of NSC fate over 10days across the entire pallial germinal zone. (A-D) Detailed views (dorsal) of groups of cells in a her4:dRFP;mcm5:eGFP;casper transgenic fish (individual fish named piwi) observed in vivo through the skin and skull over four time points (t1-t4) spanning 10days. (A) Example of a gliogenic (self-renewing) division with asymmetrical outcome at time t4. The circle outlines an RG cell expressing RFP and GFP on the first and following days, which divided at t4 to give rise to two daughter cells (asterisks) that maintained GFP expression but only one of which (bottom cell) expresses RFP (and harbors a process, not shown). Top panel: merged channels; bottom panels: red channel only. (B) Examples of two other gliogenic (self-renewing) divisions with asymmetrical outcome at time t4. The magenta arrowhead indicates an RG cell expressing RFP on the first day, switching on GFP at t2 and dividing at t4 to give rise to two daughter cells (circles), both non-proliferating, one expressing RFP (and harboring a process, not shown). The cyan arrowhead indicates an RG cell expressing RFP and GFP on the first and following days and dividing at t4 to give rise to two daughter cells (circles), one expressing GFP and the other RFP (and harboring a process, not shown). Asterisks indicate two quiescent cells that serve as references. (C) Example of a symmetric gliogenic division. The circle indicates an RG cell expressing RFP on the first day, then switching on GFP and dividing to give rise to two identical RFP-positive, GFP-negative (quiescent) daughter cells (asterisks). (D) Example of an RFP-positive RG cell (yellow arrowhead) losing RFP expression over the time course of analysis; this is interpreted as the cell switching fate and delaminating into the parenchyme. Scale bars: 20µm (A-D).