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. Author manuscript; available in PMC: 2017 Jun 6.
Published in final edited form as: Dev Cell. 2016 Jun 6;37(5):444–457. doi: 10.1016/j.devcel.2016.05.004

Figure3. Papillar development is refractory to frequent chromosome structural aberrations.

Figure3

A.Example of chromosome structure in 8N mitotic papillar cell 5 days after IR induced during endocycles. Acentric fragments (yellow arrows, 2X magnified inset in A’) and chromosome fusions (white arrows) are indicated. B.Diploid genital imaginal disc karyotype, from animal irradiated at the same time as cells in A. C.Number aberrations/cell from irradiated wild-type octoploid (8N WT) papillar and diploid WT (2N WT) imaginal disc cells. D.Distribution of acentric/fused chromosomes from same animals as in C. Compare C,D to unirradiated data in Fig2C,D. A-D from N=70 and N=54 polyploid and diploid cells respectively. The increased incidence of aberrant karyotypes in 8N vs. 2N is significant when accounting for increased chromosomes in 8N cells (Chi square, p<.0001). E.Time-lapse of papillar mitosis after IR induced during endocycles. CenpC-Tomato=kinetochores (KTs, purple), histone H2AV=DNA (green, nuclear), and Moesin-GFP=cell membranes (Memb, green). Time is in minutes relative to anaphase onset. Example of lagging acentric DNA (white arrow, 2x magnified and contrast-enhanced insets) that segregates into daughter nuclei. Yellow arrow at 17:00 highlights contractile ring. F.Distribution of mitotic defects in 8N papillar cells after IR, scored from time-lapse data. Note- the percentage of cells with acentric DNA is likely an under-estimate, due to the co-existence of centromere-containing DNA that overlaps acentric DNA in some cases. G.Avg. time from anaphase onset to cytokinesis furrow initiation. IR divisions were binned into those with/without detectable errors. *= significant change from No IR or IR with normal mitosis (Two-tailed T-test, p<.001). Error bars= standard deviation. Data in E-G from N=113 IR divisions, from numerous replicates. H.WT adult rectum. DNA-purple, papillae-pseudo-colored green. I.WT adult rectum in animals irradiated during endocycles. J.Adult papillar cell number in WT, from control and IR (induced during endocycles). N= 13-23 animals counted/condition from multiple replicates. Yellow bars=mean. DAPI=DNA in all images. White scale bar=5 μm, Yellow scale bar=50 μm.