Fig. 2. Cpeb knockdown mice. (A) Schematic representation of the transgene construct. The Zp3 promoter was inserted upstream of the Egfp open reading frame, which was followed by 1301 bases of the Cpeb 3' UTR in an inverted repeat structure separated by irrelevant loop sequence. The Cpeb inverted repeats would form a double-stranded stem and be cleaved by DICER, thus yielding siRNAs that would anneal to the endogenous Cpeb 3' UTR and induce RNA destruction. (B) RT-PCR of Egfp, Cpeb, Mos, Zp3 and -tubulin mRNAs from ovary extracts derived from 2-month-old animals. (C) Ovaries from 8-week, 2-, 4- and 10-month-old animals were fixed, embedded and stained with hematoxylin and eosin. The Cpeb knockdown ovaries displayed a progressive decrease in oocyte number and follicles. (D) TUNEL labeling of 6-week-old ovaries from wild-type and TG mice. Note that while the wild-type ovary displayed little labeling, the TG ovary was heavily labeled, indicating substantial granulosa cell apoptosis. Scale bars: 100 µm in C,D.