Numerous transcription factors that regulate trophoblast developmental processes have been identified; however, the regulation of trophoblast-specific gene expression has not been definitively characterized. While a new role of Gata3 in trophoblast development was being demonstrated in mice, we examined effects of GATA transcription factors on conceptus interferon tau (IFNT), a major trophectoderm factor in ruminants. In this study, expression patterns of trophoblast
ASCL2, CDX2, CSH1, ELF5, HAND1, IFNT, and
TKDP1 mRNAs were initially examined, from which
ASCL2, CDX2, IFNT, and TKDP1 mRNAs were found to be similar to those of
GATA2 and
GATA3 in days 17, 20, and 22 (day 0=day of estrus) bovine conceptuses. A chromatin immunoprecipitation (ChIP) assay revealed that endogenous GATA2 and GATA3 occupied GATA binding sites on the upstream regions of
CSH1, IFNT, and
TKDP1 genes and on the intron 1 region of
CDX2 gene in bovine trophoblast CT-1 cells. In transient transfection analyses of the upstream region of bovine
CSH1, and
IFNT or the intron 1 region of
CDX2 gene, over-expression of
GATA2 induced transactivation of these trophoblast-specific genes in bovine non-trophoblast ear fibroblast EF cells, but over-expression of
GATA3 did not substantially affect their transactivation. In CT-1 cells, endogenous
CDX2 and
IFNT mRNAs were down-regulated by
GATA2 siRNA, while endogenous
ASCL2 and
CDX2 mRNAs were down-regulated by
GATA3 siRNA. Our results indicate that in addition to trophectoderm lineage specification, GATA2 and/or GATA3 are involved in the regulation of trophoblast-specific gene transcription in bovine trophoblast CT-1 cells.
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