title: Stable S/MAR-based episomal vectors are regulated at the chromatin level.
abstract: Episomal vectors assembled from defined genetic components are a promising alternative to traditional gene therapy vectors that integrate in the host genome and may cause insertional mutations. The vector pEPI-eGFP is stably retained in the episomal state in cultured mammalian cells at low copy number for many generations without integration into the host genome. Although pEPI-eGFP is a fully engineered vector, little is known about how it interacts with the host genome and about the molecular mechanisms that are responsible for its transcriptional activity. We have analyzed the expression of the episomal reporter gene eGFP under conditions that affect the chromatin state of the genome. We have also constructed pEPI derivatives carrying a tandem array of lac operator sequences, which allows in vivo visualization and manipulation of the chromatin state of the episome. We show that changes in chromatin state of both the host and pEPI-eGFP induces changes in episomal gene activity and influences the episome's nuclear distributions. We conclude that episomal genes are subject to control systems of the host, similarly to their counterparts in the host genome.
authors.affiliation: Swammerdam Institute for Life Sciences, University of Amsterdam, P.O. Box 94215, 1090GE, Amsterdam, The Netherlands. f.tessadori@hubrecht.eu
authors.forename: Federico
authors.initials: F
authors.lastname: Tessadori
authors.forename: Kang
authors.initials: K
authors.lastname: Zeng
authors.forename: Erik
authors.initials: E
authors.lastname: Manders
authors.forename: Martijn
authors.initials: M
authors.lastname: Riool
authors.forename: Dean
authors.initials: D
authors.lastname: Jackson
authors.forename: Roel
authors.initials: R
authors.lastname: van Driel
mesh_terms: D000107:Acetylation; D000818:Animals; D016466:CHO Cells; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D017405:Herpes Simplex Virus Protein Vmw65 / Q000235:genetics; D006657:Histones / Q000378:metabolism; D007399:Interphase; D007763:Lac Operon; D008745:Methylation; D051379:Mice; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: D002843:Chromatin; D017405:Herpes Simplex Virus Protein Vmw65; D006657:Histones; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins