Methotrexate–treated embryos maintain expression of appropriate developmental markers. Expression patterns were visualized via whole-mount in situ hybridization in embryos treated with 400 μM MTX and fixed at shield stage (A-H), tailbud (I-P), and 24 hpf (Q-W’). While MTX-treated embryos at 24hpf are clearly delayed with respect to normal development, they do express appropriate developmental markers: krt18 –enveloping layer, gsc – involuting cells and neural plate, ntl – blastomere margin, notochord and dorsal organizer, foxA2 – involuting cells and neural plate, crestin – neural crest, myoD – paraxial mesoderm, hgg- hatching gland (anterior most structure), ngn – CNS. (A-J) Animal view, dorsal to the right. (K-P) Lateral view with dorsal view inset. (Q, R, R’, T, V, W, X, X’) Dorsal view. (S, U, V’) Lateral view. (T’) ventral view.
Lee et al. BMC Developmental Biology 2012 12:12 doi:10.1186/1471-213X-12-12