QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 16 March 2005
doi: 10.1242/dev.01780

This Article Summary Full Text Full Text (PDF) An erratum has been published Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ji, J.-Y. Articles by Schubiger, G. Search for Related Content PubMed PubMed Citation Articles by Ji, J.-Y. Articles by Schubiger, G.

Genetic interactions between Cdk1-CyclinB and the Separase complex in Drosophila

Jun-Yuan Ji^*,, Justin Crest and Gerold Schubiger

Department of Biology, University of Washington, Seattle, WA 98195-1800, USA

View larger version (27K): [in a new window]   Fig. 1. Cytogenetic map of Drosophila chromosome regions covering thr (A), pim (B) and sse (C). Bars designate deficiency lines: red bars are enhancers, blue bars are suppressors and black bars are deficiencies that do not alter the six cycB blastoderm phenotype. The cytogenetic region for thr (A) is based on published data by D'Andrea et al. (D'Andrea et al., 1993) and Philp et al. (Philp et al., 1993). The region covering pim (B) is based on information from FlyBase and the region that covering sse (C) is based on data from Jäger et al. (Jäger et al., 2001).

View larger version (20K): [in a new window]   Fig. 2. The onset of anaphase is regulated by both Cdk1-CycB activity and the Pim-Thr-Sse complex in a dose-dependent manner. The durations of cell-cycle phases are measured by analyzing timelapse recordings using two-photon microscopy in embryos with different levels of CycB and different components of Pim-Thr-Sse complex between cycles 6 and 11. The duration of prophase-metaphase and anaphase-telophase do not change between cycle 6 and 11 (Ji et al., 2004), thus data are averages of the duration from 10-20 time-lapse recordings of each genotype between cycle 6 and 11. Prophase-metaphase duration is 220 seconds in wild-type embryos (51 measurements from 20 embryos, s.d.=30 seconds); 270 seconds in four cycB embryos (51 measurements from 18 embryos, s.d.=40 seconds); 350 seconds in thr1/four cycB embryos (24 measurements from 11 embryos, s.d.=60 seconds); 240 seconds in pim1/four cycB embryos (33 measurements from 10 embryos, s.d.=30 seconds) and 230 seconds in sse13m/four cycB embryos (52 measurements from 11 embryos, s.d.=30 seconds). When compared with four cycB embryos, the differences caused by lower thr, pim or Sse levels are significant (P<0.0002). There is no significant difference in the duration of anaphase-telophase in the five genotypes (duration varies between 160-180 seconds).

View larger version (72K): [in a new window]   Fig. 3. The cycle 10 phenotype of two cycB (A), six cycB (B), sse13m/six cycB (C, suppressor) and thr1/six cycB (D,D', enhancer) embryos. Embryos were stained with antibodies against histone (green) and phosphorylated histone H3 (red); areas stained with both appear yellow. In two cycB, six cycB and suppressor embryos, all nuclei are in interphase (green), except for polar body nuclei arrested in metaphase of cycle 1 (yellow in B,C). The enhancer (D,D') embryos have many nuclei in mitosis (yellow). Note that there are many micro/macro-nuclei and chromosomal bridges, as well as asynchronous mitoses, in thr/six cycB embryos (D'). The images are projections of 20 optical sections with a 3-µm interval. Scale bars: in A, 50 µm; in D', 10 µm.

View larger version (170K): [in a new window]   Fig. 4. Pattern of nuclear cortical migration from late telophase at cycle 9 to early interphase of cycle 10. A projection of time-lapse recordings collected with 10-second intervals reveals the patterns. Genotypes of the embryos are labeled above images; posterior (A,B,D) and anterior (C) parts of the embryos are shown. Arrows (A-D) trace the direction of nuclear movement over 120 seconds. Note the straight movement in A, the meandering pattern in B, and the curved movement in C and D. Insets (a1-a3, b1-b3, c1-c3 and d1-d3) are images with 30-second intervals during cortical migration. Images in a1, b1, c1 and d1 begin at slightly different time-points, because most nuclei move in and out of focal planes during the recording. Scale bars: in D, 40 µm for A-D; in d3, 10 µm for all insets.

View larger version (172K): [in a new window]   Fig. 5. The morphology of the microtubule network at cycle 9 interphase when nuclei move to the cortex (A-C, shown at higher magnification in A'-C'), and astral microtubule morphology at cycle 9 metaphase (A''-C''). (A-A'') two cycB embryo; (B-B'') six cycB embryo; (C-C'') sse13m/six cycB embryo. These embryos were stained with an antibody against tubulin to label microtubules and with rhodamine-conjugated anti-histone H1 antibody to label nuclei for precise staging (not shown). Images in A-C and A'-C' are projections of 11 optical sections with a 1.5-µm interval. Images in A''-C'' are projections of six sections with 1-µm intervals. Note that interphase microtubules in the sse13m/six cycB embryo (C,C') are stronger than those in two cycB embryos (A,A'), but the astral microtubules in metaphase sse13m/six cycB embryo are not different from six cycB embryos (B'',C''). Scale bars: in C, 40 µm for A-C; in C', 20 µm for A'-C'; in C'', 10 µm for A''-C''.