title: Pregnancy and interferon-tau induce conjugation of bovine ubiquitin cross-reactive protein to cytosolic uterine proteins.
abstract: Conceptus-derived interferon-tau (IFN-tau) induces bovine endometrial ubiquitin cross-reactive protein (UCRP) mRNA and protein on Days 15-21 of pregnancy. Bovine UCRP retains the Leu-Arg-Gly-Gly C-terminal sequence of ubiquitin that ligates to and directs degradation of cytosolic proteins. The objectives of the present experiments were to determine whether UCRP became conjugated to endometrial cytosolic proteins during early pregnancy and in response to recombinant bovine (rbo) IFN-tau. Ubiquitin (8 kDa), UCRP (17 kDa), and conjugates thereof (> or = 30 kDa) were quantitated using Western blotting and densitometry. Endometrial ubiquitin and its conjugates did not differ between Day 18 pregnant and nonpregnant cows, or between control and rboIFN-tau-treated (25 nM) explant cultures (Day 14; nonpregnant). Bovine UCRP was induced in endometrium from pregnant as compared with nonpregnant cows. Conjugation of endometrial proteins to UCRP was induced in pregnant as compared to nonpregnant cows. Recombinant boIFN-tau induced UCRP and its conjugates in cultured endometrial explants from nonpregnant cows. It is concluded that UCRP, in response to rboIFN-tau, becomes conjugated to endometrial cytosolic proteins during early pregnancy. The regulation of uterine proteins by UCRP may be integral to the maintenance of early pregnancy in ruminants.
authors.affiliation: Department of Animal Science, University of Wyoming, Laramie 82071-3684, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Johnson
authors.forename: K J
authors.initials: KJ
authors.lastname: Austin
authors.forename: E A
authors.initials: EA
authors.lastname: Van Kirk
authors.forename: T R
authors.initials: TR
authors.lastname: Hansen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D003600:Cytosol / Q000737:chemistry; D003720:Densitometry; D005260:Female; D007370:Interferon Type I / Q000494:pharmacology*; D008969:Molecular Sequence Data; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000494:pharmacology*; D011270:Pregnancy, Animal / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D014452:Ubiquitins / Q000031:analogs & derivatives* / Q000378:metabolism; D014599:Uterus / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D002352:Carrier Proteins; D007370:Interferon Type I; D011257:Pregnancy Proteins; D011506:Proteins; D011994:Recombinant Proteins; D014452:Ubiquitins; C020947:interferon tau