Multiple interferon tau (IFNT) genes exist in bovine. An antiluteolytic substance secreted by the bovine conceptus and primarily responsible for maternal recognition of pregnancy is bovine trophoblast protein 1 (bIFNT1), one of new type I interferon tau (IFNT) genes. The objectives of this research were to investigate whether multiple, distinct gene encode bIFNT1 and other type I bIFNT gene in the bovine genome or not and to examine the expression of bIFNT1 and other bIFNTc1 mRNAs during conceptus development. The transcription of these genes could be regulated through caudal-related homeobox-2 (CDX2) and ETS2 and/or AP1(JUN) expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. The presence of mRNAs encoded by bIFNT1 and type I bIFNTc1 genes were examined quantitatively via reverse transcription-polymerase chain reaction (RT-PCR) analysis of total cellular RNA (tcRNA) extracted from on the days 17, 20 and 22 bovine conceptuses. bIFNT1 was highly expressed on the day 17 and transcripts were gradually and weakly detectable on the days 20 and 22. However, the other bIFNTc1 gene examined transcripts was highly expressed on the day 20 and transcripts were weakly detectable on the days 17 and 22 bovine conceptuses. Furthermore, human choriocarcinoma JEG3 was co-transfected with an -1kb-bIFNT1/c1-Luc constructs and several transcription factor expression plasmids. Compared to each -1kb-bIFNT1/c1-Luc increased when this constructs were co-transfected with, ETS2, AP1(JUN), CREBBP and/or CDX2. Also, bIFNTc1 gene was had higher effect on activity by alone ETS2, and AP1(JUN) expression factors in choriocarcinoma JEG3 cell. However, bIFNT1 gene expression of the upstream region was not idented. These results demonstrate that these genes display differential, tissue-specific expression and developmental regulation during pregnancy.