Fig. 2. In the midbrain, increasing levels of Snail2 expression coincide with a decrease in Cad6B transcript and protein prior to neural crest EMT. Time-course of the transcript (whole-mount in situ hybridization) and protein (immunohistochemistry) distribution of Snail2 and Cad6B in the midbrain region during the period of EMT, just prior to the onset of neural crest cell emigration. Cad6B transcripts are initially detected in the midbrain region at the 4-5 somite stage (ss), but are diminished as both Snail2 transcripts and protein are upregulated. Interestingly, Cad6B protein is present after its transcripts are no longer detected up until 6 ss, and is eliminated at 7 ss, just one stage before the onset of neural crest cell migration from this region. Arrowheads identify midbrain boundaries.