Fig. 2. Molecular lesions, TAC-1 and ZYG-9 distribution in three new tac-1 temperature-sensitive mutant alleles. (A) Schematic representation of TAC-1 (1-260) showing the position and nature of the mutations identified in the three new tac-1 alleles. Cyan box, TACC domain. (B-I) One-cell-stage embryos during mitosis in the wild-type (B,C) and tac-1 temperature-sensitive mutant alleles shifted at 25°C for >12 hours (D-G) or maintained at 15°C (H,I). B,D,F,H: ZYG-9 and -tubulin staining; C,E,G,I,: TAC-1 and -tubulin staining. Left panels show ZYG-9 or TAC-1 staining alone, right panels the merge of ZYG-9 or TAC-1 (red), -tubulin (green) and DNA (blue). The histograms on the right of each staining series represent the quantification of ZYG-9 and TAC-1 levels in the cytoplasm (white bars) and the ratio between the levels of ZYG-9 or TAC-1 at centrosomes and in the cytoplasm (black bars) (Materials and Methods). Values are given as the mean ± s.e.m.; a.u., arbitrary units relative to the wild-type values, which have been set to 1 (dashed lines). Numbers of embryos analyzed for TAC-1 and ZYG-9 were: wild type, 17 and 13; tac-1(or369) plus tac-1(or402): 19 and 18; tac-1(or455), 10 and 10; tac-1(or455) [15]: 11 and 14. Anterior is left, posterior is right; bars, =10 µm.