Control of Apoptosis by Asymmetric Cell Division
Figure 4
dnj-11, ces-1, and ces-2 Are Involved in Orienting the Mitotic Spindle of the NSM Neuroblasts
(A) Epifluorescent images shown are maximum projections of Z-series of a wild-type embryo carrying the transgene Phis-24his-24::gfp. The scale bar represents 5 μm. Ventral is to the left and dorsal to the right. The Z-series were taken every 60 s during a 4-min time period. Chromosomal DNA in the NSM neuroblast prior to the division is indicated by white arrows. Between minute 1 and minute 2, the NSM neuroblast starts dividing. The chromatids of the NSM (indicated by orange arrows) move toward the ventral side, the chromatids of the NSM sister cell (indicated by blue arrows) move to the dorsal side.
(B) (Upper panel). Epifluorescence images of six consecutive focal planes of the Z-series at minute 3 shown in (A) as maximum projection. Medial to lateral planes are shown from left to right. The chromatids of the ventral NSM are located medially. The chromatids of the dorsal NSM sister cell are located laterally. (Lower panel). Six consecutive focal planes of a Z-series of a ces-2(bc213) embryo. Medial to lateral planes are shown from left to right. The chromatids of the ventral NSM are located laterally. The chromatids of the dorsal NSM sister cell are located medially.
(C) Schematic representation of the ventral/dorsal and medial/lateral positions of the chromatids of NSM and NSM sister cell (indicated in green) in wild-type embryos. The blue rectangle indicates the cleavage plane of the NSM neuroblast.
(D) Quantification of the orientation of the cleavage planes observed. The complete genotypes of the embryos analyzed from top to bottom were: dtIs372; dnj-11(bc212) bcls25; dtls372, ces-2(bc213); bcls25; dtls372, and ces-1(n703); bcIs25; dtIs372.