... Primary motoneuron Muscle pioneer Single-cell transplants Mosaic analysis Laser ablation Genetic mapping Formation of appropriate connections between motoneurons and their target muscles is essential for animals to carry out their normal behaviors. En route to their targets, motor axons...

... in the zebrafish slow-muscle-omitted (smu) gene disrupt many developmental processes involving Hedgehog signaling. smu −/− embryos have a 99% reduction in the number of slow muscle fibers and a complete loss of Engrailed-expressing muscle pioneers. In addition, mutant embryos have partial cyclopia, and defects...

... radially away from the notochord, becoming a superficial layer of muscle cells. A subset of adaxial cells develop into engrailed -expressing muscle pioneers. Adaxial cells differentiate into slow muscle fibers of the adult fish. We have named the lateral population of cells in the segmental plate, lateral...

... pattern of development of each muscle is the same in all three pairs of legs. The extensor tibiae (ETi) forms a giant syncytium, or supramuscle pioneer, which then breaks up into a series of muscle pioneers. The flexor tibiae muscle (FITi) is formed directly by sequential addition of individual muscle...