Fig. 8. Model of CSN5/CSN function during oogenesis (modified from Ghabrial and Schupbach, 1999). In region 2a of the germarium, meiotic recombination begins with the formation of DSBs under the control of mei-W68 (McKim and Hayashi-Hagihara, 1998). These breaks are repaired by proteins of the recombination repair pathway, including the spindle-class genes. The progress of DSB repair is monitored by a mei-41-dependent checkpoint. If DNA damage persists, as it does in CSN5 or spindle-class mutants, the checkpoint is activated and Vasa is modified to a form that prevents efficient translation of grk message. The ensuing underproduction of Grk protein leads to axial patterning defects (Ghabrial and Schupbach, 1999). We propose that the role of CSN5 is either to limit the production of DSBs, perhaps by promoting Mei-W68 turnover, or to stabilize one of the repair proteins, thereby promoting repair and bypass of the mei-41-dependent checkpoint.