Abstract: 80

REGULATION OF EMBRYONIC GENOME ACTIVATION AND COMPACTION BY THE TRANSFER OF CYTOPLASM TREATED WITH INHIBITORS OF PROTEIN SYNTHESIS OR PROTEIN KINASE IN MOUSE.

Lee DR^{1 2} , Lee JE² , Yoon HS² , Roh SI² , Kim MK¹
Dept of Biology, Hanyang Univ, Seoul, Korea ¹
Infertility Research Cntr, Jeil Women's Hospital, Seoul, Korea. ²

To investigate the origin and action mechanism of cytoplasmic factor as a regulator of the genome activation and morphogenesis, the embryonic development, RNA synthesis and protein phosphorylation were examined in reconstructed embryos. A half of 1-cell mouse embryo with both pronuclei was electrofused with the enucleated cytoplasm of 1- or 2-cell embryos which were cultured for 24 h from post hCG 20 h in CZB with or without cycloheximide(CHX, an inhibitor of protein synthesis; P+P-CHX group), genistein(Gen, an inhibitor of tyrosine protein kinase; P+2-Gen group) and 6-dimethylaminopurine(6-DMAP, an inhibitor of serine-threonine protein kinase; P+2-DMAP group), and co-cultured with Vero cells for 5 days. And their development, cell numbers at compaction, [5, 6-³H]uridine incorporation into RNA and the pattern of protein phosphorylation after labeling of [³²P]orthophosphate were compared with the reconstituted embryos such as P+2 or P+P(control group). Embryonic development and time of RNA synthesis in P+P-CHX were similar to those in P+P. But time and cell stages of embryonic compaction in P+P-CHX were similar to those in P+2. The compaction was initiated at 4-cell in P+2 and P+2-Gen and at 8-cell in P+P and P+2-DMAP. On two-dimensional gel electrophoresis, phosphorylation of 80 and 110KD proteins inhibited in the embryo of P+2-DMAP when compared with that of P+2 and P+2-Gen after 3 h of reconstruction. These results suggest that protein synthesis between 1- and 2-cell stage affects the timing of embryonic genome activation, and that cytoplasmic factor derived from oocyte or its change regulates the time schedule of embryonic compaction in mouse. Also, serine-threonine protein kinase has important role on the regulation of compaction.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.