Fig. 9. C(2)M activity is not required for association of cohesin SMCs with chromosome arms or centromeres. (A) Single nuclei from wild-type (WT) and c(2)M^EP[2115] whole-mount preparations immunostained for SMC1/3 (green), CID (orange), and C(3)G (magenta). In wild-type region 2A and region 3 nuclei, the brightest spots of SMC1/3 staining correspond to the CID signal that marks the centromeres (open arrows). Although chromosome cores are absent in c(2)M mutant germaria, patches/foci of SMC1/3 still coincide with CID (solid arrows), indicating that cohesin SMCs localize to centromeres in the absence of C(2)M function. Images are projections of a deconvolved Z-series. Bar, 2 µm. (B) Germarial chromosome spread preparations from wild-type (WT) and c(2)M^EP[2115] mutant (c(2)M^–/–) females expressing GFP-ORD were immunostained for SMC1/3 (green), GFP-ORD (orange), and C(3)G (magenta). In c(2)M mutants, all nuclei display diffuse SMC1/3 and ORD signal that is similar to that of WT pro-nurse cell nuclei that do not assemble SC. Note also that all c(2)M mutant nuclei exhibit enrichment of SMC1/3 and ORD signal at the centromeres of pro-oocytes and pro-nurse cells (open and solid arrows, respectively). Bar, 10 µm.