Somite defects in PAX3-FKHR transgenic animals resulted in skeletal malformations that included rib fusions and mis-attachments.     ///    "We reported that PAX3-FKHR interferes with normal Pax3 developmental functions, with mice exhibiting neural tube and neural crest abnormalities that mimic those found in Pax3-deficient Splotch mice. "    ///    "Embryos from the transgenic line expressing the highest levels of PAX3-FKHR had severe neural tube defects, including exencephaly, and almost half of the embryos died between gestational ages E13.5-E15.5. "    ///    We previously developed transgenic mice expressing PAX3-FKHR under the control of mouse Pax3 regulatory sequences to test this hypothesis.     ///    "Here we expanded those studies to show that developmental expression of PAX3-FKHR results in aberrant myogenesis in the developing somites and neural tube, leading to ectopic skeletal muscle formation in the mature spinal cord. "    ///    Gene expression profiling indicated that PAX3-FKHR expression in the developing neural tube induces a myogenic pattern of gene expression at the expense of the normal neurogenic program.     ///    "Transgenic mice expressing PAX3-FKHR have multiple defects in muscle development, including ectopic skeletal myogenesis in the developing neural tube.. "    ///    "These studies reveal a prominent role for PAX3-FKHR in disrupting Pax3 functions and in deregulating skeletal muscle development, suggesting that this fusion protein plays a critical role in the pathogenesis of alveolar RMS by influencing the commitment and differentiation of the myogenic cell lineage.. "    ///    "The resulting PAX3-FKHR fusion protein contains PAX3 DNA-binding domains fused to the potent transactivation domain of FKHR, suggesting that PAX3-FKHR functions to deregulate PAX3-specific target genes and signaling pathways. "