...Scott M. Paulissen; Daniel M. Castranova; Shlomo M. Krispin; Margaret C. Burns; Javier Menéndez; Jesús Torres-Vázquez; Brant M. Weinstein ABSTRACT The pectoral fins of teleost fish are analogous structures to human forelimbs, and the developmental mechanisms directing their initial growth...

... understood. Here, we show that in zebrafish the transcription factor foxc1a is dispensable for trunk motor nerve guidance but is required to guide spinal nerves innervating the pectoral fins, equivalent to the tetrapod forelimbs. In foxc1a null mutants, instead of converging with other nerves at the plexus...

... pectoral fin induction in the aldh1a2/neckless mutant with exogenous RA and by blocking RA signaling in wild-type embryos, we find that RA acts as a permissive signal that is required during the six- to eight-somite stages for pectoral fin induction. Cell-transplantation experiments show that RA production...

...- expressing cells in the lateral plate mesoderm in wild-type and fgf24 mutant embryos between 18 hpf and 32 hpf. At 18 hpf, tbx5 expression is indistinguishable in wild-type and fgf24 mutants( Fig. 7A,B ). However, at 27 hpf, the tbx5 -expressing cells have congregated towards the pectoral fin bud...

... zebrafish cDNA libraries using chick fgf10 as a probe and cloned zebrafish fgf10 ( Fig. 2A ). As has been previously reported in mouse and chick embryos( Ohuchi et al., 1997 ), at 24 hpf, prior to initial budding of the pectoral fins, zebrafish fgf10 can be detected in the LPM of the presumptive...

... transcription factors that play important roles in cell-type specification and morphogenesis. In a screen for mutations affecting zebrafish cardiac function, we isolated the recessive lethal mutant heartstrings , which lacks pectoral fins and exhibits severe cardiac dysfunction, beginning with a slow heart rate...

... pectoral fin bud to maintain signaling from the apical fold, which is homologous to the AER of tetrapods. dak acts synergistically with Shh to induce fgf4 and fgf8 expression but independently of Shh in promoting apical fold morphogenesis. The failure of dak mutant fin buds to progress from the initial fin...