Fig 7.

Maternal lin-52 is required for early embryonic development. The dominant female-sterile method was used to generate female germ line clones that were homozygous for the lin-52⁹³ null mutant in the absence or presence of a lin-52⁺ transgene. w¹¹¹⁸ females were used as a control. Wild-type zygotic gene expression was provided by mating these females to w¹¹¹⁸ males. (A) Hatch rate analysis of embryos derived from females of the indicated genotype. Depletion of lin-52 in the female germ line results in a maternal-effect lethal phenotype that can be rescued by a transgene carrying a lin-52 genomic rescue construct. (B) Embryos (60 to 90 min after egg laying) were stained with propidium iodide (PI) to detect nuclei. Eggs derived from lin-52⁹³ females (C) exhibit a reduced number of nuclei compared to eggs from wild-type mothers (B). (D) Quantitation of the number of nuclei in lin-52⁹³ or wild-type eggs. (E) Wild-type embryos (0 to 30 min after egg laying) showing different stages of mitosis. (F to J) Embryos derived from the lin-52⁹³ mutant germ line (30 to 60 min after egg laying) displaying various mitotic defects. (F to H) Embryos were stained for DNA (PI, red), microtubules (alpha-tubulin, green), and a centrosome component (Cnn, blue). One or both centrosomes are often missing from mitotic spindles. (I and J) Embryos were stained for DNA (PI, red) and microtubules (alpha-tubulin, green) only. Additional defects include a broad spindle with no centrosomes (F), a branched spindle with no centrosomes (G), or an elongated spindle with no centrosomes (H). Abnormal chromosome distribution was often observed in mutant embryos (I and J).