The cellular proteins that bind specifically to the Epstein-Barr virus origin of plasmid DNA replication belong to a gene family.
This laboratory has previously reported that a tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate ("12-O-tetradecanoylphorbol 13-acetate"), induces BJAB cells, a Burkitt lymphoma cell line, to express cellular proteins that bind to the origin of plasmid DNA replication (oriP) of Epstein-Barr virus. These oriP-binding proteins interfere with the EBV-encoded nuclear antigen EBNA-1, which binds to oriP in Raji cells. To further characterize these proteins, a lambda phage expression cDNA library made from phorbol ester-induced BJAB cells was screened for fusion proteins which bind to oriP. Two recombinant phages containing sequences encoding beta-galactosidase fusion proteins and designated lambda-OBP-1 and lambda-OBP-2 were identified. lambda-OBP-1 and lambda-OBP-2 contained 0.43 kbp and 0.61 kbp of BJAB cell cDNA, respectively, of which 395 bp were shared. Using lambda-OBP-1 as probe, two cDNAs of 1.4 kbp and 1.2 kbp, designated OBP-1 and OBP-2, respectively, were isolated. These cDNAs also shared the 395-bp sequence at the 3' end. With these cDNAs as probes, Northern blot analyses of mRNA from BJAB cells gave 1.4, 2.4, and 3.4-kb bands, but a Southern blot of human genomic DNA revealed one band. It is likely that the oriP-binding proteins were derived from spliced mRNA(s) of a gene family.
Zhang
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Laboratory of Virology, Tampa Bay Research Institute, St. Petersburg, FL 33716.
Nonoyama
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D000595:Amino Acid Sequence; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000235:genetics; D003001:Cloning, Molecular; D004261:DNA Replication; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015723:Gene Library; D004854:Herpesvirus 4, Human / Q000254:growth & development*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D014779:Virus Replication
D018076:DNA, Complementary; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C086607:OriP-binding protein 1; C086608:OriP-binding protein 2; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins