Stable S/MAR-based episomal vectors are regulated at the chromatin level

• Published in: Chromosome research Vol. 18; no. 7; pp. 757 - 775
• Main Authors: Tessadori, Federico, Zeng, Kang, Manders, Erik, Riool, Martijn, Jackson, Dean, van Driel, Roel
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.11.2010; Springer Netherlands; Springer Nature B.V
• Subjects: Acetylation; Animal Genetics and Genomics; Animals; Biomedical and Life Sciences; Cell Biology; Cell Nucleus - metabolism; Cell Nucleus - ultrastructure; ChIP; CHO Cells; Chromatin; Chromatin - genetics; Chromatin - metabolism; Cricetinae; Cricetulus; Episome; gene therapy; Genes, Reporter; Genetic Vectors - genetics; Genetic Vectors - metabolism; Green Fluorescent Proteins - biosynthesis; Green Fluorescent Proteins - genetics; Herpes Simplex Virus Protein Vmw65 - genetics; Histones - metabolism; Human Genetics; In vivo; Interphase; Lac Operon; lacO/LacR; Life Sciences; mammals; Methylation; Mice; mutation; Plant Genetics and Genomics; Plasmids - genetics; Plasmids - metabolism; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - genetics; reporter genes; S/MAR; transcription (genetics); Transcriptional Activation; Vector space; lacO/LacR; Episome; In vivo; Chromatin; S/MAR; ChIP
• ISSN: 0967-3849; 1573-6849; 1573-6849
• DOI: 10.1007/s10577-010-9165-4

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.