Cement gland-specific activation of the Xag1 promoter is regulated by co-operation of putative Ets and ATF/CREB transcription factors.
The cement gland marks the extreme anterior ectoderm of the Xenopus embryo, and is determined through the overlap of several positional domains. In order to understand how these positional cues activate cement gland differentiation, the promoter of Xag1, a marker of cement gland differentiation, was analyzed. Previous studies have shown that Xag1 expression can be activated by the anterior-specific transcription factor Otx2, but that this activation is indirect. 102 bp of upstream genomic Xag1 sequence restricts reporter gene expression specifically to the cement gland. Within this region, putative binding sites for Ets and ATF/CREB transcription factors are both necessary and sufficient to drive cement gland-specific expression, and cooperate to do so. Furthermore, while the putative ATF/CREB factor is activated by Otx2, a factor acting through the putative Ets-binding site is not. These results suggest that Ets-like and ATF/CREB-like family members play a role in regulating Xag1 expression in the cement gland, through integration of Otx2 dependent and independent pathways.
Wardle
Fiona C
FC
Whitehead Institute for Biomedical Research, and Massachusetts Institute of Technology, Nine Cambridge Center, Cambridge, MA 02142, USA.
Wainstock
Daniel H
DH
Sive
Hazel L
HL
D051696:Activating Transcription Factors; D000818:Animals; D030801:Animals, Genetically Modified; D000951:Antigens, Neoplasm / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism; D051857:Otx Transcription Factors; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D050783:Proto-Oncogene Proteins c-ets; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology
D051696:Activating Transcription Factors; D000951:Antigens, Neoplasm; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; C497661:Otx2 protein, Xenopus; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D015534:Trans-Activators; D014157:Transcription Factors; C413656:XAGE1A protein, human; D029867:Xenopus Proteins; D049452:Green Fluorescent Proteins