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. 2003 Nov 21;4(12):1175–1181. doi: 10.1038/sj.embor.7400029

Figure 1.

Figure 1

mbk-2 encodes a serine/threonine kinase required for microtubule-based processes in the one-cell Caenorhabditis elegans embryo. (A) Time-lapse differential interference contrast series from recordings of wild-type (WT), mbk-2(dd5ts) and mbk-2(RNAi) embryos. In this and subsequent figures, anterior is to the left and the bar represents 10 μm. Time (s) is relative to nuclear envelope breakdown (NEB). (a) Maternal (m) and paternal (p) pronuclei at opposite sides of the cell. (b,c) In WT, pronuclei meet before NEB (t=0) whereas the male pronucleus undergoes NEB and sets up the spindle before pronuclear meeting in mbk-2(−). In most cases, the maternal pronucleus is eventually captured by the spindle (32/37 in dd5ts; 14/15 in RNAi embryos). (d) Unlike WT, the spindle forms transversely in the posterior in mbk-2(−). Arrowheads indicate spindle poles. (e) At the two-cell stage, multiple nuclei and ectopic furrows are visible in mbk-2(−). (B) Fixed embryos stained for α-tubulin (red) and DNA (blue) at prometaphase in WT and mbk-2(dd5ts). The spindle axis is transverse and MTs less frequently reach the cellular cortex in mbk-2(dd5ts). (C) Average length of astral MTs in WT and mbk-2(dd5ts). MTs were visualized as in (B). The ten longest MTs from each centrosome were measured in five embryos of each genotype. (D) Schematic structure of the MBK-2.A protein. The grey box indicates the serine/threonine kinase domain, where the dd5ts mutation is located (asterisk).