Influence of recipient cytoplasm cell stage on transcription in bovine nucleus transfer embryos

摘要: Nucleus transfer for the production of multiple embryos derived from a donor embryo relies upon reprogramming nucleus so that it behaves similar to zygotic nucleus. One indication is RNA synthetic activity. In normal bovine embryogenesis, maternally transcripts up 8-cell stage, at which time begins transcribe its own RNA. In this experiment, synthesis was detected in (NTE) and control by pulsing with 3H-uridine, fixation, autoradiography on semithin sections. NTE were produced using either MII phase (nonactivated) cytoplasts 32 hr maturation or S-phase (activated) activated calcium ionophore A23187 cycloheximide treatment ∼8 prior fusion blastomere an in-vitro-produced morula stage maturation. Control 3H-uridine-labelled fixed 2-, 4-, early 8-, late stages. similarly prepared 1, 3, 20 postfusion stages. In embryos, absent stages, whereas all present. nonactivated (MII phase) cytoplasts, there sharp decline 1 3 after total absence fusion. contrast, (S exhibited continued high levels moderate fusion, although had ceased (activated cytoplasts), no seen 2-cell stage. However, 4-cell weak none observed those cytoplasts. At nearly showed synthesis. We conclude differs between reconstructed cytoplast former undergoing slower cessation earlier resumption synthesis, occurring as © 1996 Wiley-Liss, Inc.