title: An episomally replicating vector binds to the nuclear matrix protein SAF-A in vivo.
abstract: pEPI-1, a vector in which a chromosomal scaffold/matrix-attached region (S/MAR) is linked to the simian virus 40 origin of replication, is propagated episomally in CHO cells in the absence of the virally encoded large T-antigen and is stably maintained in the absence of selection pressure. It has been suggested that mitotic stability is provided by a specific interaction of this vector with components of the nuclear matrix. We studied the interactions of pEPI-1 by crosslinking with cis-diamminedichloroplatinum II, after which it is found to copurify with the nuclear matrix. In a south-western analysis, the vector shows exclusive binding to hnRNP-U/SAF-A, a multifunctional scaffold/matrix specific factor. Immunoprecipitation of the crosslinked DNA-protein complex demonstrates that pEPI-1 is bound to this protein in vivo. These data provide the first experimental evidence for the binding of an artificial episome to a nuclear matrix protein in vivo and the basis for understanding the mitotic stability of this novel vector class.
authors.affiliation: Institute of Cell Biology, Stockumer Strasse 10, University of Witten/Herdecke, D-58448 Witten, 1Heinrich Pette-Institute, University of Hamburg, Hamburg, Germany.
authors.forename: Bok Hee C
authors.initials: BH
authors.lastname: Jenke
authors.forename: Christian P
authors.initials: CP
authors.lastname: Fetzer
authors.forename: Isa M
authors.initials: IM
authors.lastname: Stehle
authors.forename: Franziska
authors.initials: F
authors.lastname: Jönsson
authors.forename: Frank O
authors.initials: FO
authors.lastname: Fackelmayer
authors.forename: Harald
authors.initials: H
authors.lastname: Conradt
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bode
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Lipps
mesh_terms: D000818:Animals; D026501:Blotting, Southwestern; D015153:Blotting, Western; D016466:CHO Cells; D002945:Cisplatin / Q000378:metabolism; D006224:Cricetinae; D005822:Genetic Vectors / Q000378:metabolism*; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins / Q000378:metabolism*
chemical_list: D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins; D002945:Cisplatin