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Fig. 3. Tau protein expression began at early stages of axon outgrowth and increased with neuronal development through adulthood. (A–C) Parasagittal views
of st. 22, 29/30 and 37/38 embryos processed for tau immunofluorescence in whole-mount and imaged by confocal laser-scanning microscopy. Images were
taken with the 109 (NA 0.5) objective and represent maximal intensity projections created from stacks of 26, 17 and 20 optical sections, respectively, with
voxel sizes of 1.8 9 1.8 9 8.0 lm (A and B) and 2.5 9 2.5 9 7.8 lm (C). At st. 22 (A), representing early axonal outgrowth, tau immunoreactivity was most
intense in axon tracts within the hindbrain (arrow) and ventral spinal cord (S.C.), and was also visible in peripheral motor axons projecting to anterior somites.
At st. 29/30 (B), representing a stage of maximal axonal outgrowth, tau immunoreactivity became more intense throughout the brain and spinal cord, and could
be visualized in axons of the trigeminal nerve (Vmd, mandibular branch of the trigeminal nerve). By st. 37/38 (hatchling tadpole; C), tau immunoreactivity was
abundant in axon tracts throughout the brain and spinal cord, in the retina (eye), and cranial nerves (X, vagus; IX, glossopharyngeal; VII, facial; Vmd). The
image in (C) was cropped when rotated. (D) Tau immunoreactivity in neuronal perikarya and axons within a transverse section through the ventral diencephalon
of a juvenile frog. The bracket indicates the optic tract. The image is a single optical confocal laser-scanning microscopy section taken with the 209 objective
(NA 0.75), with a pixel size of 0.45 9 0.45 lm. (E and F) Tau immunoreactivity within transverse sections through the retina of a juvenile frog at low (E) and
high (F) magnifications. Images are single confocal laser-scanning microscopy optical sections taken with the 209 objective (NA 0.75) with the scan zoom at
0.7 and 2.0, and pixel sizes of 0.60 9 0.60 lm and 0.45 9 0.45 lm for (E) and (F), respectively. Abbreviations: GCL, ganglion cell layer; INL, inner nuclear
layer; IPL, inner plexiform layer; ONL, outer nuclear layer; OPL, outer plexiform layer; PL, photoreceptor layer. Scale bars: 100 lm (A–E); 20 lm (F). |
