Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2005
Publication Date: 7/20/2005
Citation: Ishida, S., Matsuda-Minehata, F., Qin, J., Iizuka, M., Manabe, N., Echternkamp, S.E., Christenson, R., Imakawa, K. 2005. Regulation of ovine interferon-tau gene by a blastocyst specific transciption factor, CDX-2 [abstract]. Biology of Reproduction. (Supplement):93. (Abstract #54) Interpretive Summary:
Technical Abstract: Expression of ovine interferon-tau (oIFNtau), a factor essential for the process of maternal recognition of pregnancy in ruminant ungulates, is restricted to the trophoblast. However, molecular mechanisms by which oIFNtau expression is restricted to the trophoblast cells have not been fully elucidated. The homeobox gene Cdx-2, a transcription factor and a homologue of the Drosophilae gene caudal, has been implicated in the control of cell differentiation in the trophectoderm and the intestinal epithelium in mice. The objective of this study was to determine whether oIFNtau gene transcription could be regulated through Cdx-2 expression. Transcriptional regulation of the 5'-upstream region (-654 base pairs, bp) of oIFNtau gene was examined using a luciferase reporter assay system and the transcription factors, Ets-2, c-jun and/or Cdx-2, in three cell types; human choriocarcinoma JEG3, goat trophoblast like HTS-1 and unrelated NIH3T3 cells. In JEG3 and HTS-1 cells, transcription of the oIFNtau-luciferase reporter construct was increased by co-transfection of the reporter construct with the Cdx-2 expression plasmid. The increase was further enhanced by Cdx-2 and Ets-2 co-expression. In JEG3, oIFNtau-luciferase reporter transcription with co-expression of Cdx-2, Ets-2 and c-jun was increased more than 30 times compared to the oIFNtau-luciferase transcription without any transcription factor co-expression. Transcription of the oIFNtau-luciferase was enhanced substantially in NIH3T3 cells when the cells were transfected with the Cdx-2 expression construct. To determine which Cdx-2 binding sites function, deletion studies in the 5'-upstream region of the oIFNtau gene representing -551 bp, -440 bp, -274 bp and -123 bp were performed. When the upstream regions from -654 bp to -274 bp were examined, the expression of the oIFNtau-reporter construct was enhanced by Cdx-2 alone or in combination with other transcription factors; whereas Cdx-2 co-expression was not effective for the -123 bp construct. These findings were confirmed with gel-shift assays examining Cdx binding sites of the oIFNtau gene's upstream region. Results indicate that oIFNtau transcription is regulated by Cdx-2, and suggest that Cds-2 is a key molecule in determining oIFNtau gene transcription.