Fig. 1. Expression of Mater in mice with targeted mutation. (A) Northern blot of total RNA (0.6 µg) from 10-day-old ovaries isolated from wild-type, Mater^tm/+ and Mater^tm/tm mice. After separation by gel electrophoresis and transfer to nylon membrane, blots were hybridized with ³²P-labeled Mater or Zp2 (control) cDNA, washed and imaged. (B) Immunoblot of ovulated eggs (10) isolated from wild-type, Mater^tm/+ and Mater^tm/tm mice. Proteins were separated by SDS-PAGE and transferred to nitrocellulose. Blots were probed with peptide affinity-purified antibody to MATER and visualized by chemiluminescence. (C) Two-dimensional gels of de novo synthesized proteins in one-cell (a-c) and two-cell (d-f) mouse embryos, collected from gonadotrophin-stimulated, mated females 24 and 43 hours after administration of hCG, respectively. After in vitro labeling with [³⁵S]methionine/[³⁵S]cysteine, 30 embryos were focused on isoelectric gels (pH 4-7) and separated by SDS-PAGE. After visualization with fluorography, radioactivity was rendered red (wild type, a,d) or green (Mater^tm/tm, b,e) and merged (c,f). Size (kb) is indicated on the left (A) and molecular masses (kDa) are indicated on the left (B) or right (C).