RNA-SYNTHESIS IN PORCINE BLASTOMERE NUCLEI INTRODUCED INTO IN-VITRO MATURED OOPLASM

The objective was to investigate the RNA synthesis in porcine blastome re nuclei upon transplantation into in vitro matured enucleated oocyte s. Nuclei from 2- to 8-cell porcine embryos were introduced into the o oplasm of in vitro matured and enucleated porcine oocytes by electrofu sion, and the resultant reconstructed embryos were cultured in vitro. Before fusion or at different intervals after this event embryos were incubated with [H-3]-uridine, fixed, and histologically processed for autoradiography in order lo detect RNA synthesis. About two thirds of the embryos were considered to depict normal development. All blastome res displayed pronounced RNA synthesis before fusion, at 3 and 9 h aft er fusion the synthesis decreased or ceased, and at 24-49 h some embry os resumed synthesis at the 1- to 2-cell stage.