Figure 1

Western blots analysis of CABYR oligomers in mouse sperm. Immunoreactive CABYR isoforms were observed after non-reducing and reducing 1-D PAGE or 2-D PAGE using antisera specific to mouse CABYR-A and CABYR-B. CABYR-A containing isoforms (A) migrated in the non-reduced state (lane 1) as both high and low molecular weight complexes, with bands particularly prominent at about 200, 100, and 80 kDa. Upon reduction (lane 2), the immunoreactive CABYR-A containing isoforms migrated at 80, 50, and 30 kDa. CABYR-B (C) containing isoforms in the non-reduced state (lane 1) showed immunoreactive bands at 200, 100, 50, and 40 kDa, and upon reduction (lane 2) the major immunoreactive bands ran at 50 and 40 kDa with a high molecular weight complex at 100 kDa being noticeably absent upon reduction. In both cases, strips incubated with the corresponding pre-immune control sera were negative (A3, C3). 2-D Western blots of mouse CABYR-A (B) and CABYR-B (D) showed that the pI 4.0, 80 kDa spot is the dominant CABYR-A only variant. This isoform displays a modest degree of charge and mass polymorphism compared to the other variants located in the neutral region, which contain both CABYR-A and CABYR-B and show a remarkable degree of charge and mass polymorphism. All protein spots that were immunoreactive for CABYR-B (D) aligned with CABYR-A immunoreactive spots (B). The absence of spots unique to CABYR-B stained gels indicates that proteins containing only CABYR-B are not translated in mouse sperm.