title: Ontogeny of Ha-ras and c-myc mRNA levels in rabbit embryo and extraembryonic tissues by quantitative in situ hybridization.
abstract: A large variety of proto-oncogenes are known to be of key importance in cellular growth and differentiation during embryonic development. Using quantitative in situ hybridization, we studied in detail the levels of the proto-oncogenes Ha-ras and c-myc mRNA in embryos and extraembryonic tissues (maternal and embryonic placentas, trophoblast, and endometrial epithelium) during prenatal life of rabbit. cDNA probes encoding for Ha-ras (fragment Kpn 1-BstE II of 883 bp) and c-myc (fragment Pst 1-Pst 1 of 490 bp) were used to detect specific transcripts in fixed cryostat sections. High levels of Ha-ras and c-myc mRNA were detected in the rabbit embryo as well as in the decidua and in the trophoblast as early as day 9 of gestation. At 12 and 15 days of gestation, Ha-ras and c-myc mRNA levels decreased in both embryonic and maternal placenta while in the embryo a significant increase of Ha-ras and c-myc expression was detected with particular evidence in the central nervous system. Finally, at 25 days of gestation the expression of the two proto-oncogenes, Ha-ras and c-myc, was greatly decreased in both the embryo and extraembryonic tissues, and was undetectable by 30 days of gestation. These results show that in rabbit the expression of the two proto-oncogenes Ha-ras and c-myc is localized in the same tissues with similar intensity and follows an unparallel temporal modulation in the embryo and in the extraembryonic tissues during prenatal development.
authors.affiliation: MRC Group in Molecular Endocrinology, C.H.U.L. Research Centre, Québec, Canada.
authors.forename: M G
authors.initials: MG
authors.lastname: Martinoli
authors.forename: R D
authors.initials: RD
authors.lastname: Lambert
authors.forename: F
authors.initials: F
authors.lastname: Pothier
authors.forename: G
authors.initials: G
authors.lastname: Pelletier
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D015342:DNA Probes; D004622:Embryo, Mammalian / Q000737:chemistry; D004717:Endometrium / Q000737:chemistry; D005260:Female; D005629:Frozen Sections; D015870:Gene Expression; D016259:Genes, myc; D011905:Genes, ras; D009693:Nucleic Acid Hybridization; D010920:Placenta / Q000737:chemistry; D011247:Pregnancy; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis / Q000302:isolation & purification*; D011817:Rabbits / Q000196:embryology* / Q000235:genetics; D014018:Tissue Distribution; D014327:Trophoblasts / Q000737:chemistry
chemical_list: D015342:DNA Probes; D012333:RNA, Messenger