Fig. 3. Increased -HIS2AV in late pachytene oocytes of DSB repair defective mutants. All oocytes were stained for -HIS2AV (red), ORB (green) and DNA (blue) and, unless otherwise noted, were in region 3 (late pachytene). (A) -HIS2AV foci are rare in region 2a nuclei (a lower magnification image to show more nuclei) and (B) abundant in a region 3 oocyte from a spnB^BU female. (C) Region 2b and (D) region 3 oocytes from the same okr^WS mutant germarium, showing that the foci become brighter in more posterior oocytes, which are in a later stage of pachytene. In both spnB and okr mutants, large numbers of foci were present in every region 3 oocyte examined (n>20 for each genotype). By contrast, nuclear -HIS2AV foci were absent in region 3 oocytes from (E) His2Av^CT; spnB^BU His2Av⁸¹⁰ (F) and okr^WS mei-W68¹ females. (G) Nuclear -HIS2AV foci were present in okr^WS; c(3)G⁶⁸ double mutants, suggesting that a few DSBs are made in the absence of SC. (H) In a region 3 oocyte from an okr^Z0682 mutant female, -HIS2AV foci are present, but less abundant than in an okr^WS mutant. All images are maximum projections of the sections needed to view the entire nucleus. Bar, 5 µm; images B-H are approximately the same scale.