Fig. 2

Embryonic expression of zebrafish gcm2. (a, b, c) Whole mount in situ hybridisation detected gcm2 transcripts in the pharyngeal arches. Transcripts were detected in arches 3–6 at 50 hpf and by 96 hpf were present in distinct buds at the surface of the arches. Lateral view of 50 hpf embryo (a) showing expression in arches 3–6. Ventral view of 96 hpf embryo (b) showing expression specific to the developing gill arches and not impinging on the ventral midline. Ventro-lateral view of the left gill arches (c) showing expression of gcm2 in gill filament buds (arrowhead). (d, e) Sections through the pharyngeal arches of embryos post in situ hybridisation for gcm2. At 76 hpf (d) and 96 hpf (e), expression was restricted to the pharyngeal external (lateral) ectodermal epithelium surrounding arches 3–6 (labelled). Rostral is to the left of the image and medial to the top, Y = yolk. Scale bars indicate 50 μm. (f–h) Whole mount in situ hybridisation detected gcm2 expression in a population of superficial epidermal cells. Expression of gcm2 in dispersed cells (arrowhead) at 12 hpf (f) and 20 hpf (g). (h) Cross-section demonstrating that the gcm2 expressing cells (arrowhead) are immediately sub epithelial (Y = yolk, scale bar = 50 μm). (i) RT-PCR detection of gcm2 transcripts during zebrafish embryogenesis and in adult tissues. cDNA templates for lanes (left to right) are 2–24 hpf (staged every 2 h), 48 and 72 hpf staged embryos; testis (T); brain (B); eggs and ovaries (O); muscle (M); crude skin and adipose extract (I); spleen (Sp); liver (L); airbladder (A); kidneys (K); genomic DNA (gDNA) and water (H₂0). β-actin control is shown below. gcm2 transcripts were first detected in 10 hpf cDNA, and throughout development to 72 hpf. Expression of gcm2 was also detected in cDNA from adult brain, testis and a crude skin and adipose tissue extract. The primers spanned introns and amplified larger fragments from gDNA.