Bovine interferon-tau stimulates the Janus kinase-signal transducer and activator of transcription pathway in bovine endometrial epithelial cells

Trophoblastic bovine interferon-tau (blFN-tau) suppresses luteolytic pulses of endometrial prostaglandin F-2 alpha (PGF(2 alpha)) at the time of mater nal recognition of pregnancy. This results in maintenance of the corpus lut eum in cattle. The hypothesis that effects of blFN-tau in the endometrium w ere through activation of the Janus kinase (JAK)-signal transducer and acti vator of transcription (STAT) pathway of signal transduction was tested. Wh ole cell, cytosolic, and nuclear extracts from bovine endometrial cells tre ated with blFN-tau were analyzed by immunoprecipitation, immunoblotting, an d electrophoretic mobility shift assays in a series of dose- and time-depen dency experiments. Bovine IFN-tau stimulated tyrosine phosphorylation, homo - and heterodimer formation, nuclear translocation, and DNA binding of STAT proteins 1, 2, and 3, Moreover, blFN-tau induced synthesis of interferon-r egulatory factor. In conclusion, blFN-tau stimulates the JAK-STAT pathway i n the bovine endometrium. It is proposed that activation of the JAK-STAT pa thway is involved in regulating the antiluteolytic effects of blFN-tau.