Accumulation of SLBP in maturing oocytes. A) Immature oocytes were collected immediately after isolation from the follicle (0 h) or were allowed to mature for the indicated period of time. They were immunoblotted using antibodies recognizing SLBP or MAPK1/3 (loading control). Only oocytes that had undergone GVBD were collected at the 3 h/4 h and later time points, and only those containing a polar body at 12 h and later time points. Fifty oocytes per lane. Upper panel shows a representative blot; lower panel shows cumulative results of a different series (note different time points) of six replicates. B) Immature oocytes were incubated for 18 h in the presence of dbcAMP to prevent maturation, and in the presence or absence of an inhibitor of protein synthesis, puromycin, or proteasomal activity, MG132, or both; 80 oocytes per lane. Left panel shows a representative blot; right panel shows cumulative results of 3 replicates using MG132. Means were compared using the t-test. Error bars indicate the standard error of the mean.