Interferon-tau and pregnancy.
A type I interferon known as IFN-tau is expressed massively by the outer epithelium (trophectoderm) of the preimplantation trophoblast of ruminant ungulate species, such as cattle and sheep, for a few days during early pregnancy. They signal to the mother that she is pregnant and indirectly prevent regression of the corpus luteum so that progesterone production is maintained and normal ovarian cyclicity avoided. Despite their clear roles as reproductive hormones, the IFN-tau have the typical antiviral, antiproliferative, and immunomodulatory activities of other type I IFN. They are most closely related to the 172 amino acid IFN-omega. Unlike other type I IFN, they are not virally inducible and appear to be produced constitutively as the trophectoderm first forms during the development of the blastocyst. The discovery of the IFN-tau illustrates the diverse activities of interferons and their likely involvement in the normal embryonic development of mammals. The diversity of mechanisms different groups of mammals use to prolong the functional life span of the corpus luteum in early pregnancy is probably the consequence of genetic conflict between the genes of the mother and her offspring, which has led to remarkably high rates of change in placental structure and trophoblast signaling mechanisms.
Roberts
R M
RM
Departments of Pathobiology and Animal Sciences, College of Veterinary Medicine, University of Missouri, 104 Connaway Hall, Columbia, MO 65211, USA.
D000818:Animals; D002417:Cattle; D005260:Female; D007370:Interferon Type I; D007371:Interferon-gamma / Q000096:biosynthesis*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000096:biosynthesis*; D011270:Pregnancy, Animal / Q000378:metabolism*; D012418:Ruminants / Q000378:metabolism*; D012756:Sheep
D007370:Interferon Type I; D011257:Pregnancy Proteins; C020947:interferon tau; D007371:Interferon-gamma