Changes in -Tubulin Protein Distribution in Zebrafish (Danio rerio) Oocytes and the Early Cleavage-Stage Embryo
Figure 2
Cellular distribution of -tubulin in early cleavage embryos imaged with an epifluorescence microscope. (a), (b), and (c) represent 1-cell, 2-cell, and 4-cell (becoming 8 cell) stage zebrafish embryos, respectively. (Top) Nuclei within blastomeres were stained with DAPI (red, arrow heads point to nuclei); yolk cell nonspecifically stains with DAPI. (Middle) -tubulins were stained with GTU-88 (green); bar equals 100 μm; -Tubulin is predominately found in blastomeres compared to yolk cells. (Bottom) “Merged” panels are a composite of both DAPI and GTU-88 staining. (a) Fertilization-stage embryo with a pronucleus (arrow) but no centrosomes only diffuse -tubulin staining in the blastodisc cytoplasm. (b) 2-cell stage with distinct punctate -tubulin clusters (p) in putative centrosomes polarized on opposite sides of the nuclei. (c) 4-cell embryo dividing into 8-cell stage; one bank of cells (upper) is in focus, while the other bank (lower) is not. The curvilinear or arc-shaped/ring (A/R) arrays of -tubulin (i.e., putative centrosome arrays) are particularly striking and extensive at this stage (c).
