Developmental regulation of transcription factor AP-2 during Xenopus laevis embryogenesis.
We have isolated a cDNA clone encoding the Xenopus homologue of the transcription factor AP-2 (XAP-2). The predicted amino acid sequence derived from the Xenopus cDNA shows very strong conservation with the amino acid sequence of human AP-2, suggesting that this protein is evolutionarily conserved, at least among vertebrates. This is further substantiated by the demonstration that an in vitro translation product of XAP-2 cDNA bound specifically to an AP-2 binding site from the human MT-IIA gene. Northern blot analysis of Xenopus embryo RNA revealed the existence of three major XAP-2 mRNA species that were only detectable after the midblastula transition (when embryonic transcription is activated), with peak accumulation of the transcripts occurring during gastrulation. Therefore, in contrast to other Xenopus transcription factors, XAP-2 is not maternally derived but arises exclusively from zygotic transcription. Unlike the situation in cultured human teratocarcinoma (NT2) cells, retinoic acid treatment did not induce XAP-2 mRNA in Xenopus embryos, even though the treatment had a pronounced morphogenetic effect on the embryos. Our results suggest that XAP-2 may play a distinctive role during Xenopus embryogenesis.
Winning
R S
RS
Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
Shea
L J
LJ
Marcus
S J
SJ
Sargent
T D
TD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics*; D014212:Tretinoin / Q000494:pharmacology; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics
D004268:DNA-Binding Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D029867:Xenopus Proteins; C493675:tfap2a protein, Xenopus; D014212:Tretinoin