Figure 1.

Neuronal Birthdating from her4-Expressing RGs In Vivo

(A) Genetic strategy. Top: 9-tert-butyldoxycycline (9TB) triggers stable H2a-mCherry and transient GFP activation in her4-positive RGs in double-transgenic animals for the depicted constructs. Bottom: neurons generated by the first RG (top, green) divisions following 9TB induction inherit detectable levels of H2a-mCherry (red). The label is lost upon successive divisions.

(B) Imaris quantification of mCherry immunostaining in 2- (left; n = 6), 3- (middle; n = 2), or 5- (right; n = 1) cell clones from different her4^H2a-mCherry animals pulsed with 9BT at 1 dpf and analyzed at 5 dpf. Top: Imaris segmentation of mCherry-positive cells in individual clones. Middle: corresponding photomicrograph. Bottom: reconstructed lineage trees and fluorescence intensities. Scale bar, 7 μm.

(C) Neuronal fate of the mCherry-labeled daughter cells of her4-positive RGs in her4^{H2a-mCherry,9BT(1dpf)} fish analyzed at 5 dpf. Triple immunocytochemistry for GS, mCherry, and HuC/D on a pallium cross-section (one hemisphere). White lines indicate pallial-subpallial boundary. Scale bar, 10 μm.

See also Figures S1–S3. Abbreviation definitions can be found in Figure S1B.