Fig. 2

 An hsp-tolloid transgene rescues the mini fin phenotype. All embryos were heat-shocked for 10 min at 37°C during late gastrulation. (A–C) Heat-shocked embryos at 1 dpf. Non-transgenic mfn embryos (A) still display the mfn phenotype (arrowheads indicate missing fin), but transgenic mfn embryos are rescued to a phenotype indistinguishable from wild type (B) or are ventralized (C), as demonstrated by excess blood (arrow) and duplicated tail fins (arrowhead). Heat-shock-treated mfn transgenic (E, H, K) and non-transgenic sibling (D, G, J) and wild type (F, I, L) embryos. (D–F) bmp4 expression at bud stage. (G–I) eve1 and goosecoid (gsc, as a control) expression at the 1-somite stage (N = 18). (J–L) msxB expression at the 20-somite stage (N = 18). Arrowheads indicate absent msxB expression domain in mfn (J), which is restored in the transgenic mutant (K). (D–L) Lateral views, dorsal to the right, anterior to the top. (M) Duplex PCR for Tg(hsp70:tld) and bmp7. All rescued wild type or ventralized embryos carry a copy of the Tg(hsp70:tld) and endogenous bmp7 (control), whereas non-rescued mutants carry only the bmp7 gene. PCR from two different transgenic lines are shown (top, line 30; bottom, line 1).