Fig. 3. Characterization of mitotic chromosome behavior in the CNS of animals lacking the baf gene: decreased histone H3 phosphorylation. (A,B) Late third instar larval CNS tissues from baf¹/+ (A), l(2)k10210/l(2)k10210 (A) or baf¹/baf¹ animals (B) were labeled with rabbit polyclonal PH10 antibodies, directed against a histone H3 Ser¹⁰ phospho-epitope (green). Staining with propidium iodide (PI) identifies DNA (red, PI/DNA). Bracket in baf¹/baf¹ (B) indicates two consecutive sections of baf¹/baf¹ tissues. Staining by PH10 was mostly negative; white arrowheads indicate the few positive condensed chromosome masses. (C,D)Behavior of mitotic chromosomes of the baf¹/+ (C) or baf¹/baf¹ (D) tissues was also examined by immunofluorescence staining using PH10 (green, P-H3). The same material was labeled with PI to identify DNA (red, PI/DNA). Colocalization is yellow (Merge). While chromosomes of prophase, prometaphase, metaphase, early anaphase and late anaphase/telophase are clearly visualized by PH10 in the baf¹/+ cells (C), chromosomes from baf¹/baf¹ cells are abnormal (D). Scale bars: 100 µm (A); 50 µm (B); 5 µm (C,D). All images were recorded with a confocal microscope.