Reporter gene expression in G2 of the 1-cell mouse embryo.
Similar amounts of expression of a luciferase reporter gene that is driven by the SV40 early promoter are detected in G2 of 1-cell mouse embryo following injection of the male pronucleus in either early or mid/late S. No luciferase activity is observed when the male pronucleus is injected in early S and the embryos analyzed for expression in late S. Last, no luciferase activity is observed when the female pronucleus is injected in mid/late S and the embryos analyzed for luciferase activity in G2 of the first cell cycle. These results suggest that zygotic gene activation initiates in the 1-cell embryo rather than in the 2-cell embryo, as previously thought, and that differences between the transcriptional activity of male and female pronuclei exist.
Ram
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PT
Department of Biology, University of Pennsylvania, Philadelphia 19104-6018.
Schultz
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RM
D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D005260:Female; D016195:G2 Phase / Q000235:genetics*; D015870:Gene Expression; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012319:RNA Polymerase II; D014158:Transcription, Genetic / Q000235:genetics*; D015053:Zygote
D012319:RNA Polymerase II