The Drosophila Microtubule-Associated Protein Mars Stabilizes Mitotic Spindles by Crosslinking Microtubules through Its N-Terminal Region
Figure 4
Overexpression of GFP-C Mars causes embryonic lethality and impairs the assembly of the mitotic spindle.
(A, B) Subcellular localization of GFP-C-Mars at interphase (A) and metaphase (B). (C–F) Defects caused by overexpression of GFP-C-Mars in embryos. (C) Overview of GFP-C-Mars overexpressing embryo showing abnormal pattern of early mitoses. (D) Giant nuclei. (E) Poorly organized mitotic spindles. (F) Excessive formation of astral microtubules. Numbers to the right of panels (D–F) indicate the frequency of the respective phenotypes. Numbers add up to more than 100% since some spindles show a combination of two or more abnormalities. 200 mitotic spindles from 10 embryos were scored. (G) Spindles from control embryo overexpressing GFP-Mars show normal morphology. Embryos were fixed and stained with tubulin antibody (red), GFP antibody (green) and DAPI (turquoise). Scale bars are 40 µm in panel (C) and 5 µm in panels (A, B, D–G). (H) Still images from live imaging of GFP-C-Mars showing fusion of two nuclei (cf. Movie S4). Scale bar is 20 µm.