Modulation of DRM composition and association with Cx43 during IVM. Sucrose density gradient centrifugation was performed on freshly isolated COCs (A and B, first panel) and COCs recovered after 4 h (A and B, second panel) and 24 h of IVM with gonadotropins (A and B, third panel). Dot blot and hybridization with CTB revealed GM1 enrichment in the DRM-containing fractions of each preparation (A). Hybridization with an anti-Cx43 antibody revealed an increase in DRM-associated Cx43 as IVM progressed (B). Alkaline phosphatase treatment of fraction 4 from gradients performed after 4 and 24 h of IVM revealed that DRM-associated Cx43 is mostly in phosphorylated form (C). The values presented under each Cx43 panel represent the percentage of Cx43 distributed in the different fraction groups. AP, Alkaline phosphatase; Ctrl, control; IB, immunoblotting; I, intermediate fractions; NR, non-raft fractions; GNT, gonadotropins.