Fig. 5

The viscerocranium and neurocranium of prdm5^hi61Tg-prdm1a^m805 double mutant exhibit more severe phenotypes than single mutants. Double prdm1a^m805 prdm5^hi61Tg heterozygotes were crossed to obtain the prdm5^hi61Tg-prdm1a^m805 double mutant embryos. A-D: Flat-mounted Alcian blue staining of the viscerocranium and neurocranium in control, prdm1a^m805, prdm5^hi61Tg mutant, and prdm5^hi61Tg-prdm1a^m805 double mutant. As compared to control (A), the prdm1a^m805 (B) mutant larva is missing the ceratobranchial 2–5 cartilages (cb2–5) as was also observed in the prdm1a morphant. The prdm5^hi61Tg (C) mutant larva has a slightly shortened Meckel′s cartilage (m) in the viscerocranium. The prdm5^hi61Tg-prdm1a^m805 double mutants (D) have a more severe phenotype in the viscerocranium (shortening of the Meckel′s cartilage, greatly widening of the angle between ceratohyals [ch], and absence of ceratobranchials 2–5). E–H: Flat mount of the neurocranium in the control (E), prdm1a^m805 mutant (F), prdm5^hi61Tg mutant (G), and the prdm5^hi61Tg-narrowminded^m805 double mutant (H). The neurocranium and ethmoid plate (ep) are slightly smaller and trabeculae are shortened in prdm1a^m805 mutant and prdm5^hi61Tg mutant (F,G). In prdm5-/-, the hypophyseal fenestra is significantly wider and the anterior basicapsilar cartilage is missing (G, arrow). The double mutant shows further reduction of the neurocranium, smaller ethmoid plate, shorter trabeculae, and missing basicapsilar cartilage (H, arrow). Anterior is to the left. abc, anterior basicapsular commissure; cbs, ceratobranchials; ch, ceratohyal; ep, ethmoid plate; m, Meckel′s cartilage; n, notochord; pch, parachordal; tr, trabeculae; * in B,D illustrates missing cbs.