Fig. 3.

(A) Abundance of SLBP during early embryogenesis. Unfertilized eggs and embryos were collected at the stages and times (hours post-hCG injection) indicated, and immunoblotted using the anti-SLBP antiserum. The inset within lanes 5–7 shows a longer exposure of the same blot. Met II, metaphase II eggs; L1c, late 1-cell; E2c, early 2-cell; L2c, late 2-cell; E4c, early 4-cell; L4c, late 4-cell. All lanes contain 25 embryos, except lane 7 which contains 100 embryos. (B) Twenty-five metaphase II oocytes (lane 1) or 1-cell (lane 2), 2-cell (lane 3), 4-cell (lane 4), 8-cell (lane 5), morula (lane 6), or blastocyst (lane 7) embryos were subjected to RT-PCR using primers derived from the mouse SLBP cDNA sequence that were expected to amplify a fragment of 800 nt. No signal was obtained when reverse transcriptase was omitted from the reaction (not shown). (C) Effect of the protein synthesis inhibitor, puromycin (PM), on SLBP quantity in early embryos. Embryos at the 1- or 2- cell stage were collected at the indicated times (hours post-hCG; lanes 1,4,7). Embryos were incubated in the presence (lanes 2,5,8) or absence (lanes 3,6,9) of puromycin for the period indicated after which embryos were analyzed by immunoblotting using the anti- SLBP antiserum. 25 embryos per lane.