Figure 4.

Intravital 2PM observation of Fucci (S/G₂/M‐Green) mice. (a) Schematic illustration of four different cell‐cycle‐associated events that can be captured in the non‐surface zone (light blue, from a basal part of the VZ to the adjacent SVZ) of the cerebral wall using the Fucci (green) system in utero. Event 1, apical‐ward movement of a G2‐phase NPC's nucleus (an mAG⁺ nucleus moves). Event 2, progression of M phase (mAG disappearance at late M phase) in a non‐surface‐dividing NPC (whose soma is large and round‐shaped). Event 3, basal‐ward movement of the nucleus or soma of a G2‐ or M‐phase NPC, which is exhibited prior to non‐surface division (event 2). Event 4, entrance of an NPC into S phase (mAG expression begins in a relatively small nucleus). (b) A time series showing apical‐ward nuclear migration typical to G2‐phase NPCs (corresponding “event 1” of Figure 4a) in an E14 Fucci embryo in utero. Scanning was performed from the basal VZ (0 μm) to the middle VZ (18 μm). Initially (0 min), the tracked mAG⁺ nucleus was most clearly detected from 8 μm to 16 μm (magenta circle) with faint/peripheral fluorescence at 4 μm and 18 μm (magenta triangle). By 25 min, it moved apically and exited the basal VZ. Scale, 10 μm