Fig. 2 Secondary motoneurons form rings around floor plate cells in flh mutant embryos. Double RNA in situ hybridizations at 36 hr with antisense probes against dm-grasp labeling secondary motoneurons (blue) and col2a1 labeling floor plate (red). Dorsal view of wildtype embryos reveals that secondary motoneurons form bilateral rows flanking the continuous floor plate (A). In flh mutants, secondary motoneurons form rings around the floor plate islands (B; n = 14 embryos, 142 floor plate islands). Note that while the antibody to Dm-grasp (Zn-5) labels both secondary motoneurons and floor plate (Fig. 1), the antisense probe to dm-grasp RNA has not been reported to label floor plate (Kanki et al., 1994). Scale bar, 50 μm.
Reprinted from Developmental Biology, 187(2), Beattie, C.E., Hatta, K., Halpern, M.E., Liu, H., Eisen, J.S., and Kimmel, C.B., Temporal separation in the specification of primary and secondary motoneurons in zebrafish, 171-182, Copyright (1997) with permission from Elsevier. Full text @ Dev. Biol.