Temporal and spatial analyses of cx30.3 mRNA expression. A: Expression of cx30.3 was detected at the 1 day post fertilization (dpf) stage, and thereafter maintained throughout embryonic development. The zebrafish ef1α gene was used as positive control to demonstrate the integrity and genomic-DNA-contamination-free status of the cDNA samples. B:cx30.3 mRNA is predominantly expressed in the adult skin, fin, inner ear, ovary, liver, heart, retina, while a relatively low level of cx30.3 expression was also detected in the gill, swim bladder, skeletal muscle, spleen, and gut. The relative level of mRNA expression was calculated by comparing ΔCt between mean Cts of zebrafish cx30.3 and ef1α.

In situ hybridization of Cx30.3 mRNA in embryos. Embryos were stained by whole-mount in situ hybridization with a cx30.3 antisense riboprobe. A,B: Signal was detected (and highlighted with arrows) in 1 days postfertilization (dpf) stage embryos, in the otic vesicle (A) and dorsal fins (B). C-H: At 2 dpf (C,G,H) or 3 dpf (D-F), cx30.3 mRNA signal was readily detected in the skin (C), the inner ear (D), the lateral line (E,G), and the fins (C). F,H: Sense-probe controls are shown.

Sections of cx30.3 in situ hybridization stained embryos. Embryos were stained by whole-mount in situ hybridization with cx30.3 antisense riboprobe, embedded in plastic and 5-μm sections were cut with a microtome. Only sections from embryos at 2 days postfertilization (dpf) are shown, the staining pattern in later stage embryos is similar. A: Transverse cross-section of embryonic eyes, showing a lack of staining of the probe. B: The developing inner ear with probe labeling the otic vesicle (arrow). C: A transverse section of the embryonic fish tail and fin, with probe accumulating around the peripheral skin and on the fin (far right).