Early transcriptional activation of the hsp70.1 gene by osmotic stress in one-cell embryos of the mouse.
In fertilized mouse eggs, de novo transcription of embryonic genes is first observed during the S phase of the one-cell stage. This transcription, however, is mostly limited to the male pronucleus and possibly uncoupled from translation, making the functional meaning obscure. We found that one-cell mouse embryos respond to the osmotic shock of in vitro isolation with migration of HSF1, the canonical stress activator of mammalian heat shock genes, to pronuclei and by transient transcription of the hsp70.1, but not hsp70.3 and hsp90, heat shock genes. Isolated growing dictyate oocytes also display a nuclear HSF1 localization, but, in contrast with embryos, they transcribe both hsp70.1 and hsp70.3 genes only after heat shock. Intranuclear injection of double-stranded oligodeoxyribonucleotides containing HSE, GAGA box or GC box consensus sequences, and antibodies raised to transcription factors HSF1, HSF2, Drosophila melanogaster GAGA factor, or Sp1 demonstrated that hsp70.1 transcription depends on HSF1 in both oocytes and embryos and that Sp1 is dispensable in oocytes and inhibitory in the embryos. Hsp70.1 thus represents the first endogenous gene so far identified to be physiologically activated and tightly regulated after fertilization in mammals.
Fiorenza
Maria Teresa
MT
Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Psychology, Section of Neuroscience, UniversityLa Sapienza of Rome, 00185 Rome, Italy.
Bevilacqua
Arturo
A
Canterini
Sonia
S
Torcia
Simona
S
Pontecorvi
Marco
M
Mangia
Franco
F
D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002970:Cleavage Stage, Ovum / Q000378:metabolism*; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics; D000076249:Heat Shock Transcription Factors; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D009997:Osmotic Pressure; D011247:Pregnancy; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; C490017:Hsf1 protein, mouse; D014157:Transcription Factors; C081884:heat-shock protein 70.1; D004247:DNA