Episomal gene expression vectors offer a safe and attractive alternative to integrating vectors. Here we describe the development of a high capacity episomal vector system exploiting human episomal retention sequences to provide efficient vector maintenance and regulated gene expression through the delivery of a genomic DNA locus. The iBAC-S/MAR vector is capable of the infectious delivery and retention of large genomic DNA transgenes by exploiting the high transgene capacity of herpes simplex virus type 1 (HSV-1) and the episomal retention properties of the scaffold/matrix attachment region (S/MAR). The iBAC-S/MAR vector was used to deliver and maintain a 135 kb genomic DNA insert carrying the human low density lipoprotein receptor (LDLR) genomic DNA locus at high efficiency in CHO ldlr(-/-) a7 cells. Long-term studies on CHO ldlr(-/-) a7 clonal cell lines carrying iBAC-S/MAR-LDLR demonstrated low copy episomal stability of the vector for >100 cell generations without selection. Expression studies demonstrated that iBAC-S/MAR-LDLR completely restored LDLR function in CHO ldlr(-/-) a7 cells to physiological levels and that this expression can be repressed by approximately 70% by high sterol levels, recapitulating the same feedback regulation seen at the endogenous LDLR locus. This vector overcomes the major problems of vector integration and unregulated transgene expression.

An S/MAR-based infectious episomal genomic DNA expression vector provides long-term regulated functional complementation of LDLR deficiency.

MANSERVIGI, Roberto;
2007

Abstract

Episomal gene expression vectors offer a safe and attractive alternative to integrating vectors. Here we describe the development of a high capacity episomal vector system exploiting human episomal retention sequences to provide efficient vector maintenance and regulated gene expression through the delivery of a genomic DNA locus. The iBAC-S/MAR vector is capable of the infectious delivery and retention of large genomic DNA transgenes by exploiting the high transgene capacity of herpes simplex virus type 1 (HSV-1) and the episomal retention properties of the scaffold/matrix attachment region (S/MAR). The iBAC-S/MAR vector was used to deliver and maintain a 135 kb genomic DNA insert carrying the human low density lipoprotein receptor (LDLR) genomic DNA locus at high efficiency in CHO ldlr(-/-) a7 cells. Long-term studies on CHO ldlr(-/-) a7 clonal cell lines carrying iBAC-S/MAR-LDLR demonstrated low copy episomal stability of the vector for >100 cell generations without selection. Expression studies demonstrated that iBAC-S/MAR-LDLR completely restored LDLR function in CHO ldlr(-/-) a7 cells to physiological levels and that this expression can be repressed by approximately 70% by high sterol levels, recapitulating the same feedback regulation seen at the endogenous LDLR locus. This vector overcomes the major problems of vector integration and unregulated transgene expression.
2007
Lufino, Mm; Manservigi, Roberto; WADE MARTINS, R.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/471161
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