title: Expression of c-myc proto-oncogene during the early development of Xenopus laevis.
abstract: c-myc proto-oncogene expression in Xenopus laevis oocytes and developing embryos has been investigated. Stage VI oocytes as well as unfertilized eggs contain a high level of Xenopus c-myc mRNA (1-2.5 x 10(7) copies). However, this high level of maternal c-myc mRNA declines gradually during the time of rapid and synchronous cell cleavage and becomes almost undetectable after the mid-blastula transition. The zygotic genes then become activated for the first time, whereupon the amount of newly synthesized c-myc mRNA starts to increase again. The level of c-myc mRNA in the 1 day old embryo (stage 22) is comparable to that of oocyte or unfertilized egg. The finding suggest that c-myc gene products may play an important role during early embryogenesis, especially during the rapid synchronous cell cleavage period and onset of the mid-blastula transition.
authors.affiliation: Wistar Institute, Philadelphia, Pennsylvania 19104.
authors.forename: K
authors.initials: K
authors.lastname: Nishikura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004262:DNA Restriction Enzymes; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D004262:DNA Restriction Enzymes