a subset of replication proteins enhances origin recognition and lytic replication by the epstein-barr virus zebra protein复制的一个子集蛋白质来源识别和提高溶解性巴尔病毒复制的斑马蛋白质.pdfVIP

A Subset of Replication Proteins Enhances Origin Recognition and Lytic Replication by the Epstein-Barr Virus ZEBRA Protein 1 2 1,2,3 Ayman El-Guindy , Lee Heston , George Miller * 1 Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America, 2 Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America, 3 Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, United States of America Abstract ZEBRA is a site-specific DNA binding protein that functions as a transcriptional activator and as an origin binding protein. Both activities require that ZEBRA recognizes DNA motifs that are scattered along the viral genome. The mechanism by which ZEBRA discriminates between the origin of lytic replication and promoters of EBV early genes is not well understood. We explored the hypothesis that activation of replication requires stronger association between ZEBRA and DNA than does transcription. A ZEBRA mutant, Z(S173A), at a phosphorylation site and three point mutants in the DNA recognition domain of ZEBRA, namely Z(Y180E), Z(R187K) and Z(K188A), were similarly deficient at activating lytic DNA replication and expression of late gene expression but were competent to activate transcription of viral early lytic genes. These mutants all exhibited reduced capacity to interact with DNA as assessed by EMSA, ChIP and an in vivo biotinylated DNA pull-down assay. Over-expression of three virally encoded replication proteins, namely the primase (BSLF1), the single-stranded DNA- binding protein (BALF2) and the DNA polymerase processivity factor (BMRF1), parti