Expression of URB1 in the adult male Zebra finch brain. (A) Photomicrograph of in situ hybridization showing uniform expression of URB1 in the pallium. (B) High-power view reveals URB1 enrichment in individual pallial neurons. Note that in several of the cells indicated by the arrowheads the intracellular labelling appears more robust in the nucleus than in the surrounding cytoplasm, forming a pattern reminiscent of a fried-egg. Scale bar: 10 μm.