The Ras/Raf signaling pathway is required for progression of mouse embryos through the two-cell stage.
We have used microinjection of antisense oligonucleotides, monoclonal antibody, and the dominant negative Ras N-17 mutant to interfere with Ras expression and function in mouse oocytes and early embryos. Microinjection of either ras antisense oligonucleotides or anti-Ras monoclonal antibody Y13-259 did not affect normal progression of oocytes through meiosis and arrest at metaphase II. However, microinjection of fertilized eggs with constructs expressing Ras N-17 inhibited subsequent development through the two-cell stage. The inhibitory effect of Ras N-17 was overcome by simultaneous injection of a plasmid expressing an active raf oncogene, indicating that it resulted from interference with the Ras/Raf signaling pathway. In contrast to the inhibition of two-cell embryo development resulting from microinjection of pronuclear stage eggs, microinjection of late two-cell embryos with Ras N-17 expression constructs did not affect subsequent cleavages and development to morulae and blastocysts. It thus appears that the Ras/Raf signaling pathway, presumably activated by autocrine growth factor stimulation, is specifically required at the two-cell stage, which is the time of transition between maternal and embryonic gene expression in mouse embryos.
Yamauchi
N
N
Division of Molecular Genetics, Dana-Farber Cancer Institute, Boston, MA 02115.
Kiessling
A A
AA
Cooper
G M
GM
D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001755:Blastocyst / Q000378:metabolism; D002455:Cell Division; D002970:Cleavage Stage, Ovum / Q000378:metabolism*; D005786:Gene Expression Regulation; D008540:Meiosis; D051379:Mice / Q000196:embryology*; D008969:Molecular Sequence Data; D009028:Morula / Q000378:metabolism; D009154:Mutation; D016376:Oligonucleotides, Antisense; D015689:Oncogene Protein p21(ras) / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D027384:Oncogene Proteins v-raf; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic
D000911:Antibodies, Monoclonal; D016376:Oligonucleotides, Antisense; D015682:Retroviridae Proteins, Oncogenic; D027384:Oncogene Proteins v-raf; D015689:Oncogene Protein p21(ras)