Fig. 2. Maintenance of zebrafish hoxb1a transcription requires Hoxb1a protein. Transcription of endogenous hoxb1a was assayed by whole-mount in situ hybridization in uninjected control embryos (left-hand panels) or in embryos injected with 1 mg/ml MOb1a (right-hand panels). (A,B) 24 hour embryos: (A) hoxb1a is expressed at high levels in r4 of control embryos; (B) in the MOb1a-injected embryos, there is a reduction in transcript levels in the medial part of the neural tube. (C,D) At 36 hours, loss of medial transcription in response to MOb1a is more severe. (E,F) Transverse sections (planes indicated by red arrows in C,D, dorsal towards the top) encompassing the whole of r4 were hand cut from 36 hour embryos post in situ.
