Early Development of the Trunk Neural Crest Cells in the Egyptian Cobra Naja h. haje

Trunk neural crest cells (TNCC) are representing a model for epithelial to mesenchymal transition, this correlates the importance of studying the migration of these cells to cancer metastasis. Reptiles are unique group of animals being very morphologically diverse and their close position to synapsid leading to mammals. Recently, more publications focused on the migratory behavior of trunk NCC during embryonic development of squamates. Only one colubrid snake has been studied so far regarding the NCC migration. Here we follow the migratory behavior of TNCC with HNK1 in the elapid snake Naja h. haje from early stage to 16-20 days postoviposition. Our findings show: First, comparing the colubrid snake with the Egyptian cobra shows that both snakes overall follow the conserved TNCC migratory pathways of both birds and mammals by following the rostral and avoiding the caudal portions of the somites. Second, TNCC intra-somitic migration suggests that cobra TNCC could contribute to snake scale formation analogously to turtle shell. Third, the presence of MITF in Schwann cell precursors along developing nerves, which suggests that reptile Schwann cell precursors could have the same multipotency as mammalian migrating NCC and thus give rise to its varied derivatives. Our present results of the Egyptian cobra in combination with those on a colubrid and turtle supports intersomitic TNCC as a unique reptile phenomena.