title: The capacity of polyomavirus enhancer binding protein 2alphaB (AML1/Cbfa2) to stimulate polyomavirus DNA replication is related to its affinity for the nuclear matrix.
abstract: The nuclear matrix is thought to play an important role in the DNA replication of eukaryotic cells, although direct evidence for such a role is still lacking. A nuclear matrix-associated transcription factor, polyomavirus (Py) enhancer binding protein 2alphaB1 (PEBP2alphaB1) (AML1/Cbfa2), was found to stimulate Py replication through its cognate binding site. The minimal replication activation domain (RAD) was identified between amino acid (aa) 302 and aa 371 by using a fusion protein containing the GAL4 DNA binding domain (GAL4-RAD). In addition, the region showed affinity for the nuclear matrix and, on the basis of competition studies, binding activity for one or more proteins involved in the initiation of Py DNA replication. A leukemogenic chimeric protein, AML1/ETO(MTG8), which does not contain this region of PEBP2alphaB1/AML1, was also localized in the nuclear matrix fraction and competed for nuclear matrix association with PEBP2alphaB1 and GAL4-RAD. Moreover, AML1/ETO inhibited Py DNA replication stimulated by PEBP2alphaB1 and GAL4-RAD. The inhibition was specific for replication mediated by PEBP2alphaB1 and GAL4-RAD, and proportional to the degree of loss of these activators from the nuclear matrix, suggesting a requirement for nuclear matrix targeting in the stimulation of Py DNA replication by RAD. These results are the first to suggest a molecular link between the initiation of DNA replication and the nuclear matrix compartment.
authors.affiliation: Department of Viral Oncology, Institute for Virus Research, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606, Japan.
authors.forename: L F
authors.initials: LF
authors.lastname: Chen
authors.forename: K
authors.initials: K
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000818:Animals; D019677:Artificial Gene Fusion; D001665:Binding Sites; D050659:Core Binding Factor Alpha 1 Subunit; D050676:Core Binding Factor Alpha 2 Subunit; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016296:Mutagenesis; D015530:Nuclear Matrix / Q000378:metabolism*; D011120:Polyomavirus / Q000235:genetics* / Q000502:physiology; D011518:Proto-Oncogene Proteins; D029701:Saccharomyces cerevisiae Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D050676:Core Binding Factor Alpha 2 Subunit; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C052130:GAL4 protein, S cerevisiae; D011518:Proto-Oncogene Proteins; C493726:Runx1 protein, mouse; C493716:Runx2 protein, mouse; D029701:Saccharomyces cerevisiae Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors