Figure 5.

RFP expression in the central nervous system. A, B: Confocal images displaying RFP (+) cells in the hindbrain. A is a dorsal view of the hindbrain and B is a higher magnification of the ventral region. Note the rostral end of the hindbrain lacks RFP (+) cells (A). In the ventral region (B), axon-like structures were detected crossing the midline (arrowhead). sc, spinal cord. Scale: 50 μm. C, D: RFP (+) cells (red) in the hindbrain compared to the islet-1 GFP expressing motor neurons (green). C is a stack of confocal images. D displays a single confocal plane near the X^th (X) motor nuclei. Note that two populations (red and green) do not overlap. Scale: 50 μm. E-H: A longitudinal series of the hindbrain sections are shown from the level of III^rd, IV^th (E), V^th (F), VII^th (G), and X^th motor nucleus (H). RFP (+) cells are red and islet-1 expressing motor neurons are green. Scale: 100 μm. I, J: RFP (+) cells (red) in the hindbrain were compared to the reticular neurons stained by the tracing dye, dextran fluorescein (green). I is a stack of confocal images and J is a single plane at the level of the Mauthner cell (M). S4 through S7 indicates segment number. Scale: 50 μm (I), 20 μm (J). Magenta/Green images are provided in suppl. figure. 3.