Submission Number: ALA-4-24-8

Abstract Number: 379

THE IDENTIFICATION AND EXPRESSION OF BOVINE INTERFERON-TAU GENES DURING EARLY PLACENTAL DEVELOPMENT.

Alan D Ealy* ¹, Sandra F Larson ¹, Limin Liu ^1,2, Andrei P Alexenko ¹, James A Bixby ¹ and R Michael Roberts* ^1,2

Department of Animal Sciences, University of Missouri, Columbia, MO ¹
Department of Biochemistry, University of Missouri, Columbia, MO ²

Abstract:
The interferon-tau (IFN-[:tau:]) are Type I IFN expressed only in trophectoderm of pecoran ruminants (cattle, sheep, goats, deer) preceding placentation. They are a crucial component of maternal recognition of pregnancy in these species because they modify endometrial function in such a way that corpus luteum regression is prevented. Multiple IFN-[:tau:] genes exist in cattle, but it has remained unclear how many are expressed, the extent of variation among transcripts, and whether the different genes exhibit similar patterns of expression. Thirty-three cDNA were sequenced from reverse-transcribed bovine (bo) conceptus RNA collected at day 7, 19 and 25 of pregnancy. Sixteen were unique, and encoded ten different proteins. Two of the ten proteins were identical to previously published sequences, whereas the remaining eight were novel (GenBank numbers AF196320 to AF196327). A single day 19 conceptus yielded nine distinct cDNA from only eleven cDNA sequenced. The cDNA could be placed into three phylogenetic groupings ([:tau:]1, [:tau:]2 and [:tau:]3). All showed high sequence conservation within their open reading frames (>98% nucleotide identity; >96% amino acid identity). Concentrations of IFN-[:tau:] mRNA were greater (P < 0.05) at day 17 and 19 than at day 14 and 25, with different genes showing the same expression patterns. Genes representing different boIFN-[:tau:] groupings were cloned. Their promoter regions were conserved over the regions considered important for transcriptional activation. In summary, many IFN-[:tau:] are expressed in bovine trophoblast; their genes are probably under similar transcriptional control; and individual genes may themselves be polymorphic. .

Keywords: Pregnancy Recognition, Uterus, Embryo, Cattle

This abstract is being presented at: 8:00 AM in session:
Pregnancy and Parturition I