Proto-oncogenes and embryonic development.
The role of proto-oncogenes in embryonic development was investigated using one of the most characterized vertebrates, the amphibian Xenopus laevis. Genes which belong to the major proto-oncogene families have been detected in Xenopus genome. The developmental control of the myc gene was assayed using a characterized Xenopus myc probe and specific antibodies. The myc gene is highly expressed as a stable maternal mRNA in oocyte, and an unfertilized egg contains 5 X 10(5)-fold the myc RNA content of a proliferative somatic cell. The myc RNA store is evenly distributed in the oocyte and the egg. Fertilization triggers a post-transcriptional control of the gene and the RNA store is progressively degraded to a constitutive value of 10 to 30 myc RNA copies registered per gastrula embryonic cell. The 62K myc protein is accumulated late in oogenesis. This uncoupling of myc expression and cell proliferation appears as a specific developmental regulation of the myc gene, adapted to the series of rapid cell cleavages occurring after fertilization.
Méchali
M
M
Institut Jacques Monod, Paris, France.
Gusse
M
M
Vriz
S
S
Taylor
M
M
Andéol
Y
Y
Moreau
J
J
Hourdry
J
J
Leibovici
M
M
Brulfert
A
A
Almouzni
G
G
D000818:Animals; D015152:Blotting, Northern; D004625:Embryo, Nonmammalian / Q000502:physiology*; D005260:Female; D005306:Fertilization; D009693:Nucleic Acid Hybridization; D009865:Oocytes / Q000166:cytology*; D014176:Protein Biosynthesis; D011519:Proto-Oncogenes; D014158:Transcription, Genetic; D014982:Xenopus laevis