OBJECTIVE: The open reading frame 8 (ORF8) within the short unique (U(s)) region of the bovine herpesvirus 1 (BHV-1) genome was predicted to encode a protein with homology to U(s)9 protein of other alpha herpesviruses. The aim of this study is to identify the protein encoded by the U(s) ORF8 and to examine the effect of its expression in mammalian cells. METHODS: A polyclonal antiserum was raised against U(s) ORF8 protein expressed in Escherichia coli. A recombinant baculoviurs designated as Ac/CA8 was created by integrating U(s) ORF8 under the control of the mammalian CAG promoter into the baculovirus genome. U(s) ORF8 protein was expressed in rabbit kidney (RK13) cells transduced by Ac/CA8. RESULTS: The antiserum reacted specifically with 27-and 32-kD polypeptides from the BHV-1-infected and Ac/CA8-transduced RK13 cells. High-level expression of U(s) ORF8 protein in RK13 cells transduced by Ac/CA8 led to a distinct cytopathic effect and a reduction in cell viability; the onset of apoptotic cell death was induced as judged by DNA laddering and chromatin condensation analyses. CONCLUSIONS: These data represent the identification of BHV-1 U(s )ORF8 protein, which directly induces apoptosis in RK13 cells. Copyright 2002 S. Karger AG, Basel
OBJECTIVE: The open reading frame 8 (ORF8) within the short unique (U(s)) region of the bovine herpesvirus 1 (BHV-1) genome was predicted to encode a protein with homology to U(s)9 protein of other alpha herpesviruses. The aim of this study is to identify the protein encoded by the U(s) ORF8 and to examine the effect of its expression in mammalian cells. METHODS: A polyclonal antiserum was raised against U(s) ORF8 protein expressed in Escherichia coli. A recombinant baculoviurs designated as Ac/CA8 was created by integrating U(s) ORF8 under the control of the mammalian CAG promoter into the baculovirus genome. U(s) ORF8 protein was expressed in rabbit kidney (RK13) cells transduced by Ac/CA8. RESULTS: The antiserum reacted specifically with 27-and 32-kD polypeptides from the BHV-1-infected and Ac/CA8-transduced RK13 cells. High-level expression of U(s) ORF8 protein in RK13 cells transduced by Ac/CA8 led to a distinct cytopathic effect and a reduction in cell viability; the onset of apoptotic cell death was induced as judged by DNA laddering and chromatin condensation analyses. CONCLUSIONS: These data represent the identification of BHV-1 U(s )ORF8 protein, which directly induces apoptosis in RK13 cells. Copyright 2002 S. Karger AG, Basel