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Fig. 3. follistatinexpression in the cement gland is dependent on Pitx1. (A) Injection of pitx1 RNA results in the induction of follistatin. 400 pg pitx1 RNA was injected at early cleavage stages. RT-PCR analysis was performed on animal caps harvested at mid-neurula stages after dissection at late blastula stages. (B) Cycloheximide treatment results in strong expression of follistatin. (C) follistatin expression is observed in anterior notochord at early neurula stages. (D) follistatin expression is observed in the hindbrain (arrow) and pronephros (arrowheads) at late neurula stages. (E) 66% of uninjected late neurula stage embryos (n = 29) have detectable follistatin staining in the presumptive cement gland region. (F) 36% of embryos (n = 33) have detectable follistatin staining in the cement gland primordium following injection of Pitx1-MO and Pitx2c-MO; (G) 77% of embryos (n = 31) have expanded follistatin staining following injection of pitx1 RNA. Morpholino oligos or pitx1 RNA were injected into the animal pole of early cleavage stages embryos. Embryos in (C, D) are dorsal views, anterior to left; embryos in (E-G) are ventral views, anterior to left. Black arrows and arrowheads indicate actual or expected follistatin staining. |