Ink and casting dye injections
Embryos (E10.0 – E13.0) were dissected and placed in ice cold PBS (n≥3 per genotype in each time point). Using a pulled glass pipette, India ink or Yellow casting dye (Connecticut Valley Biological Supply) was injected into the ventricles until ink/dye penetrated small vessels. Embryos were postfixed in 10% buffered formalin for 12 hours, dehydrated and cleared in benzylbenzoate: benzyl alcohol (2:1v/v).