Expression of HOXA5 candidate target genes in the medulla oblongata analyzed by single and double in situ hybridization (ISH) on coronal cryosections of P21 mouse brains. Schematic views of coronal brain sections illustrate brain structures while square red boxes on the schemes refer to the localization of single ISH pictures. In double ISH (right column) Hoxa5 signal is in red/brown precipitate while target gene signal is in blue. Localization of double ISH pictures is illustrated by square red boxes on the single ISH pictures (middle column). (A–C) Signal of Hoxa5 and Neurod2 in the lateral reticular nucleus (LRN). (D–F) Signal of Hoxa5 and Camk4 in LRN. (G–I) Signal of Hoxa5 and Zic1 in LRN. (J–L) Signal of Hoxa5 and Cbln1 in the caudal part of the spinal nucleus of the trigeminal (SPVC). (M–O) Signal of Hoxa5 and Adcy1 in SPVC. As illustrated in the right column, many Hoxa5-positive cells also show labeling for target gene transcripts. White arrows point to examples of co-localization, while gray arrows show example of cells only positive for Hoxa5, and black arrows show example of cells only positive for target genes. n = 2–4 brains hybridized for Hoxa5 and each target genes in single and double ISH. Cb, cerebellum; MO, medulla oblongata. Medial is on the right, lateral is on the left. Scale bar 200 μm in (A,B,D,E,G,H); 500 μm in (J,K,M,N); 100 μm in (C,F,I,L,O).