CONTEXT

In the field of gene transfer, the scientific community is looking for an ideal safe and efficient vector. In particular, this vector shoud help prevent side effects related to transgene integration/ expression in host cells, e.g. in decreasing regulatory cross-talk between genomic and exogenous sequences thus reducing the risk for insertional mutagenesis.

There is thus a need for genetic elements which: (i) hold both an enhancer-blocking activity and a boundary effect, as well as (ii) show long-term stability when placed in a gene transfer vector and (iii) do not hinder the biology and replication of virus-derived vectors.

TECHNICAL DESCRIPTION

This invention describes a gene transfer vector, which includes different combinations of novel synthetic Genetic Insulator Elements (GIE). Inventors have established new GIE species derived from the CTF/NF1 binding site and/or original CTCF binding sequences (from chicken betaglobulin or human T cell receptors loci). In particular, an optimised number and structure of CTF repeats has been identified with utmost interesting properties.

Indeed, these new GIE species have been shown to efficiently insulate from genomic regulatory interference, a transgene encoded in an integrating gene transfer vector. For example, inventors have tested these GIEs in several vectors such as lentivirus or gretrovirus and identified a specific sequence of inverted repeats which performs at best.

BENEFITS

This invention allows to improve gene transfer stability and decrease genotoxicity.

– All GIE sequence sizes are < 600bp, resulting in improved stability;
– Retrovirus-derived vectors biology and infectivity are not affected, including with lentivectors;
– Transcription specificity is dramatically improved, which allows controlled expression;
– GIE properties can benefit to both non-viral and/or non integrating vectors safety and specificity

INDUSTRIAL APPLICATIONS

Vectors including these new GIE not only are already established as R&D tools, but most interestingly hold major potential for human gene therapy, whether ex vivo or in vivo.

DEVELOPMENT STAGE

Viral vectors including these GIEs have been tested in numerous human cell lines (including hES) and most importantly in human primary HSCs cells from human cord blood and NSCs.

Insulated Lentivectors exhibit dramatic improvement of both transgene expression stability, specificity and controlled regulation, as well as a potential for reduced genotoxicity while both titres and transduction efficiency are similar to non-insulated vectors. The laboratory currently is further developing these new vectors for gene therapy applications e.g. in HSCs.

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