Fig. 2

Knock-down of polaris and pkd2 gene function leads to several morphological phenotypes. Pol SP MO1 (A) and Pkd2 SP MO1 (B) morpholinos interfere with splicing of polaris and pkd2 message, respectively. RT-PCR products produced from gene-specific primers from RNA extracted from uninjected wild-type (wt) embryos versus morpholino-injected embryos are increased in size reflecting incorporation of intron sequences into the mRNAs. As an RT-PCR control, B-actin primers give the same size products from cDNAs prepared from wt and morpholino-injected embryos (B). Body shape is altered in 40 hpf morphant embryos (C–D). Polaris morphants exhibit a ventrally curved trunk and tail (D) while pkd2 morphants exhibit a dorsally curved trunk and tail (E) compared to uninjected wt embryos (C). Kidney cysts are evident in polaris and pkd2 morphants at 3 dpf (F, G). In uninjected wt embryos, wt1 expression identifies the glomerulus (g) of the pronephric kidney, while in morphants (Pol SP MO1 shown), the glomerulus appears enlarged and the pronephric tubules (pt) are distended (G). Polaris and pkd2 morphants exhibit hydrocephalus and cardiac edema at 2 dpf (H, I). Expansion of the hindbrain (single arrow) and pericardium (asterisk) is evident in morphants (Pkd2 SP MO shown, I) compared to an uninjected wt embryo (H). The direction of heart and gut looping is often reversed in 40 hpf polaris and pkd2 morphants (J–M). In a wt embryo (J), the atrium (a) of the heart loops toward the left side of the embryo while in morphants (Pol AUG MO shown) the atrium often loops toward the right side (K). In wt embryos, the liver (l) and intestinal bulb are located on the left side of the embryo (L) while in morphants (Pol AUG MO shown) these organs are often on the right side (M).