Figure 1.

Clam Cdc20 protein levels are relatively constant across the meiotic and mitotic cell cycles of clam embryos. Oocytes were fertilized at zero min. Aliquots taken at 5-min intervals were pelleted and resuspended in sample buffer. Five microliters (corresponding to ≈1,200 oocytes) of each sample was analyzed by SDS/PAGE, followed by immunoblotting with α-clam Cdc20 antibodies. GVBD is a visual indication of the progression past the G₂/M border of meiosis I. Small variations in Cdc20 levels at different time points were not reproducible between sample sets. The arrow indicates the position of clam Cdc20.