Rbm24a and Rbm24b are required for craniofacial development. Bright field, ISH, and Alcian blue images of ctrlMO, rbm24aMO and rbm24bMO embryos. 72 hpf lateral oriented embryos show expression of rbm24a and rbm24b in presumptive optic muscles, pharyngeal arch muscles, mandibular muscles, and fin bud. rbm24a shows additional expression in the otic vesicle (A). The anterior region of 72 hpf and 96 hpf embryos are shown oriented laterally for visualization of eye and mandible phenotypes (B). Bright field and ISH images of myod expression in the anterior region of dorsally oriented 72 hpf ctrlMO, rbm24aMO and rbm24bMO embryos (B rows 1 and 2). myod expression is detected in the find bud, optic muscles, pharyngeal arch muscles and mandibular muscles of uninjected embryos. Normal myod expression is diminished in rbm24aMO and rbm24bMO embryos. Bright field and Alcian blue cartilage staining of ctrlMO, rbm24aMO and rbm24bMO embryos in lateral orientation at 96 hpf (B rows 2 and 3). Normal cartilage staining is observed in the fin buds, ethmoid plate, palatoquadrate, hyomandibular and Meckel′s cartilage of uninjected embryos. Cartilage formation of these structures is ablated in rbm24aMO embryos and severely reduced in rbm24bMO embryos. Bright-field craniofacial images of RNA rescue rbm24aMO and rbm24bMO phenotypes at 96 hpf (C). rbm24aMO rescue, by co-injection of 5 ngrbm24aMO with 800 pg of capped poly-A rbm24a mRNA and rbm24bMO rescue, by co-injection of 8 ngrbm24bMO with 200 pg of capped poly-A rbm24b mRNA, show rescue of somite and craniofacial rbm24aMO and rbm24bMO phenotypes. fb, fin bud; om, optic muscles; ov, otic vesicle; ph, pharyngeal muscles; mm, mandibular muscles. white arrow, eye; black arrow, mandible; m, Meckel′s cartilage; ep, ethmoid plate; pq, palatoquadrate; hm, hyomandibular cartilage.