Figure S1.

Differences between Early Growth of OB and NCx Correlate with Mitral Cell Generation, Not with Cell Death or Inhibitory Interneuron Accumulation, Related to Figure 1

(A) Sagittal section of mouse telencephalon at E12.5 stained for activated Caspase 3 and DAPI. Arrowheads indicate Casp3+ cells. H, hippocampus; MGE, medial ganglionic eminence; OE, olfactory epithelium; Sp, septum.

(B) Quantification of linear density of Casp3+ cells in OB and NCx at the indicated ages. Values are mean + SEM; n = 3 embryos per age; t tests, ns = not significant.

(C) Sagittal sections of the olfactory bulb primordium at E12.5 and E14.5 from a transgenic mouse expressing GFP in GAD65+ cells stained for Tbr1 or GABA. Dotted lines indicate the perimeter of the OB primordium. Arrows point at the leading edge of tangentially-migrating interneurons (GAD65+ or GABA+), which are just arriving to the OB primordium by E12.5.

(D) Experimental design for mitral cell birthdating by single BrdU injections and analyses at postnatal day (P) 21.

(E) Coronal sections of mouse OB at P21 after BrdU injections at the indicated ages, stained for Tbr1 to identify mitral cells retaining BrdU. Arrow indicates a cell retaining 100% BrdU, solid arrowheads indicate cells retaining 50% and open arrowheads indicate cells retaining only 25% of BrdU.

(F and G) Quantification of the proportion of mitral cells (Tbr1+) retaining full levels of BrdU (F), or 25%, 50% and 100% of BrdU (G). Values are mean + SEM; n = 3 embryos per stage.

(H) Experimental design to identify cell types produced by apical progenitors in the OB primordium.

(I) Images from brains electroporated with Gfp. Left, external view at E18.5 showing GFP+ mitral cell axons in the lateral olfactory tract (LOT); center and right, sagittal section through the OB at P5 showing GFP+ mitral cells. GL, granule layer; MCL, mitral cell layer.

(J and K) Measurement of the length of G2+M phase of the cell cycle in apical (VZ) and basal (SVZ) progenitors of OB and NCx at E12.5, as defined by the time for BrdU saturation of PH3+ cells after cumulative BrdU labeling (n = 3 embryos per group). Values for the duration of other cell cycle phases, and total cell cycle (Tc), are indicated in (K).

Scale bars: 200 μm (A), 100 μm (C), 50 μm (E), 1 mm (E18.5 in I), 200 μm (P5 in I), 10 μm (P5 detail in I).