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Fig. 4. Wholemount in situ hybridisation of Xlmx1b. (A) Dorsal view of a stage 13 embryo showing placodal region expression. (B) A stage 15 embryo showing expression on the neural plate, along the neural folds and in the placodal regions. (C) A stage 19 embryo showing two intense patches of expression in the placodal regions, the otic anlagen. These will eventually develop into the otic vesicle and the embryos hearing system. (D) A cleared stage 21 embryo with neurons visible all down the dorsal side of the embryo. Some staining is noticeable in the anterior region, which may develop into the eye expression or the midbrain neurons. (E) A stage 24 embryo, the first stage at which expression is visible in the dorsal region of the eye. Staining is also seen in a population of migrating neural crest cells near the otic vesicle. (F) A stage 27 embryo showing neuron expression down the back. Staining is also apparent in the otic vesicle, eye and in a population of neurons in the midbrain region. (G) A stage 32 embryo showing more defined glomus and otic vesicle expression, staining in the optic nerve and neurons all down the back. (H) A stage 36 embryo showing precise expression in the eye and otic vesicle. (I) A stage 39 embryo close-up showing neuron and otic vesicle expression and a well developed glomus. (J) Cross-section through a stage 15 embryo showing exact areas of expression of Xlmx1b in the placodes and neural plate. (K,L) Cross-sections through a stage 33 embryo showing exact areas of expression of Xlmx1b in the otic vesicles, neurons, floor plate and glomus. (M) Cross-section through a stage 36 embryo showing expression of Xlmx1b in the eye. Abbreviations: A, archenteron; BB, mid-hindbrain boundary; CF, choroid fissure; E, eye; FP, floor plate; G, glomus; N, neurons; NC, neural crest cells; NF, neural folds; NP, neural plate; O, otic vesicles; ON, optic nerve; Pl , placodal regions. |