A 16-kDa protein has been identified that is secreted by the bovine endometrium in response to conceptus-derived interferon (IFN)-tau during early pregnancy. Because this uterine protein was similar in size to a human ubiquitin cross-reactive protein (hUCRP) that also was regulated by IFN, we suspected that they might be related. To test this hypothesis, uterine flushings, medium from cultured endometrium, and endometrial tissues were examined for the presence of ubiquitin-immunoreactive proteins. Immunoreacting proteins were detected through use of one-dimensional (1D)-PAGE and Western blotting with ubiquitin and hUCRP antiserum (1:500). A 16-kDa protein that cross-reacted with ubiquitin and hUCRP antisera was released by the endometrium and was present in uterine flushings from all Day 18 pregnant females examined (n = 12). The immunoreacting 16-kDa protein was absent in all nonpregnant females examined (n = 23). Regulation of this uterine protein by recombinant type I IFNs (rbIFN-tau, rbIFN-alpha, and roIFN-tau), using 0, 0.5, 5, and 25 nm of each IFN, was evaluated in nonpregnant (Day 12) heifers (n = 5) using 1D-PAGE and Western blotting. Release of the 16-kDa protein into medium was negligible in controls (0 nm IFN). For each IFN, a dose-dependent increase (p < 0.05) in release of the immunoreacting 16-kDa protein was noted. We conclude that the 16-kDa protein that is produced by the endometrium in response to IFN-tau during early pregnancy also shares epitopes with hUCRP and ubiquitin. The 16-kDa protein has been named bovine UCRP.

SUMMARYViral genomic RNA was purified from BHK-21 cells infected with epizootic haemorrhagic disease virus and the 10 dsRNA genome segments were isolated by polyacrylamide gel electrophoresis. These genome segments were translated in vitro using the rabbit reticulocyte lysate system and the synthesized proteins were detected by immune precipitation and gel electrophoresis. This allowed the assignment of protein coding to the genome segments and the identification of two additional virusspecified proteins not readily detectable in lysates of virus-infected cells.

No abstract

SUMMARYThe relationship between serotype specificity and protein structure was studied by polyacrylamide gel electrophoresis, peptide mapping and radioimmune precipitation (RIP) of structural and non-structural proteins of the five U.S. serotypes of bluetongue virus (BTV). The surface proteins, VP2 and VP5, showed the most variation in size among the serotypes. Peptide mapping of the proteins showed that VP2 is unique for each of the U.S. serotypes. The nucleocapsid and non-structural proteins showed a high degree of conservation, whereas the other surface protein, VP5, showed intermediate conservation among the serotypes. Monospecific neutralizing antiserum produced in rabbits against each serotype was used in cross-RIP against cytoplasmic extracts prepared from cells infected with each BTV serotype. There were extensive crossreactions among those proteins which showed a high degree of structural conservation, whereas VP2 was immunoprecipitated best in the homologous RIP system. Thus, a correlation between serotype specificity and protein structure was shown among the five U.S. serotypes of BTV.