to 1 hr. Sections were then transferred to cell culture membrane inserts (diameter, 13 mm; pore size, 8 μm; Costar) and incubated in culture media at 37°C, 8% O2, 5% CO2 for up to 8 days. Half media changes were performed every other day. After ~5 days in culture, Dlxi1/2b::eGFP+ cells could be detected and were subsequently imaged as described below.
