The receptor protein-tyrosine kinases, which can be defined as having a transmembrane domain, are a large and diverse multigene family found only in Metazoans . In the human genome, 58 receptor-type protein-tyrosine kinases have been identified and these are distributed into 20 subfamilies.
expression of chick EphA7 during segmentation of the central and peripheral nervous system EphA7 expression is restricted to prosomeres 1 and 2 in the diencephalon and all the rhombomeres in the hindbrain during segmentation stages. Later on, a superimposed pattern appears that correlates with the formation of several axonal tracts. In the somitic mesoderm, the expression correlates with segmentation and the guidance of both neural crest and motor axons through the sclerotomes
at embryonic day 2, Cek9 immunoreactivity is concentrated in the eye, the brain, the posterior region of the neural tube, and the most recently formed somites. Later in development, Cek9 expression is widespread but particularly prominent in neural tissues
RET is a cell-intrinsic marker that regulates hindgut colonization by sacral neural crest cells, and has the ability to promote the enteric nervous system developmental potential of sacral neural crest cells towards that of vagal neural crest cells