title: Tissue specific phenotypes of polyomavirus A and B enhancer transpositions and duplications: positional and nonpositional effects on replication in lymphoid cells.
abstract: We have extended our studies using the mouse lymphoid cell system to determine if polyomavirus (Py) cell type specificity is a consequence of the simple presence of either the A and B enhancers, or if specificity results from specific combinations or arrangements of the individual enhancer elements. Mouse fibroblasts and several T lymphoid cell lines were transfected with wild-type DNA or genomes containing either a deletion of the B enhancer, a transposition of the A and B enhancers relative to their normal positions, or a tandem duplication of either the A or B enhancers. In some cells activation of DNA replication was dependent on the simple presence of the B enhancer and not upon its position, as all genomes containing a B enhancer replicated efficiently. In other cells, deletion or transposition of the B enhancer abolished DNA replication which suggested that activation depended upon the position of this element. The A enhancer core duplication replicated well in lymphoid cell lines, but duplication of the B enhancer did not yield a generally efficient configuration. We have interpreted these results to suggest that individual enhancer components can interact via specific combinational principles to yield cell type specific effects upon Py DNA replication.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine 92717.
authors.forename: B A
authors.initials: BA
authors.lastname: Campbell
authors.forename: L P
authors.initials: LP
authors.lastname: Villarreal
mesh_terms: D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D004261:DNA Replication; D004274:DNA, Recombinant / Q000032:analysis; D004742:Enhancer Elements, Genetic; D014644:Genetic Variation; D051379:Mice; D010641:Phenotype; D011120:Polyomavirus / Q000235:genetics*; D013601:T-Lymphocytes / Q000382:microbiology*; D014162:Transfection
chemical_list: D004274:DNA, Recombinant