The Cell Cycle Timing of Centromeric Chromatin Assembly in Drosophila Meiosis Is Distinct from Mitosis Yet Requires CAL1 and CENP-C
(A) Changes in the amount of CID at centromeres during mitosis in nonstem brain cells. Larval brains were fixed and stained with anti-CID antibody (green) and DNA is stained with DAPI (red). Scale bar: 5 µM. (B) Quantification of total centromeric CID fluorescence intensity per nucleus in stages of mitosis in dividing nonstem brain cells. Condensed chromatin at metaphase and anaphase results in a reduction in antibody penetration. Bars, standard errors. Values are normalized to the interphase average. N = 318 total cells. N = 171, interphase; 35, prophase; 52, metaphase; 21, anaphase; 39, telophase/early G1. Scale bar: 5 µM. (C) Live imaging of a nonstem brain cell from anaphase into early G1 phase expressing GFP-CID (green) and the chromatin marker H2Av-RFP (red). Time elapsed is shown in minutes. Circle indicates the initiation of CID assembly between 6 and 12 min after anaphase onset. Scale bar: 3 µM. (D) Quantification of total centromeric GFP-CID fluorescence intensity per nucleus from live imaging of dividing nonstem brain cells in larvae (n = 9 movies). Time elapsed in minutes after anaphase onset is shown on the x-axis, and fold increase in total centromeric GFP-CID intensity per nucleus is shown on the y-axis. Bars, standard errors.