Monthly Featured Technologies   View all Monthly Featured Technologies Use of Human Gamma Satellite Insulator Sequences to Prevent Gene Silencing and Allow for Long Term Expression of Integrated Transgenes Description of Technology: The lack of stable expression of transgenes in target cell lines remains a serious problem for gene therapy and cellular reprogramming approaches. Once integrated into chromosomes, the expression of these transgenes may be regulated by epigenetic effects of the surrounding chromatin. These position effects, which include transgene silencing and expression variegation, are often associated with changes in the chromatin structure, and are capable of inhibiting gene expression and neutralizing the intended effect of the inserted transgene. Experimental results suggest that gene position effects can be partially overcome by flanking the transgene with regulatory elements called chromatin insulators which work by establishing defined domains of transcriptional activity within the eukaryotic genome. These insulators can partially overcome position effects by shielding the promoters from the influence of neighboring regulatory elements, or by preventing the spread of heterochromatin which can lead to subsequent gene silencing. This invention discloses the use of gamma satellite DNA, residing in the pericentromeric region of human chromosomes, as highly efficient chromatin insulators. These insulators have a remarkable ability to overcome position effects and prevent the silencing of transgenes. When human chromosome 8 gamma satellite sequences were used as flanking DNA for eGFP (enhanced green fluorescent protein) gene expression in mouse erythroleukemia (MEL) cells, stable transgene expression was recorded for well over eight months. Until recently, no chromatin insulator sequences were known to completely prevent gene silencing on a long term basis in transfected cells. The human gamma-satellite sequences demonstrate a higher efficiency than any known chromatin insulator identified so far in intergenic regions, and may have invaluable applications in the fields of gene therapy, protein expression, and cellular reprogramming where adequate expression of the transgene is essential for long term therapeutic or developmental success. Applications: Gene therapy Protein expression Cellular reprogramming Development Status: Prolonged transgene expression attained in mouse erythroleukemia (MEL) cells. Inventor: Vladimir L. Larionov, Jung-Hyun Kim, Tom Ebersole (NCI) Publications: G Felsenfeld, B Burgess-Beusse, C Farrell, M Gaszner, R Ghirlando, S Huang, C Jin, M Litt, F Magdinier, V Mutskov, Y Nakatani, H Tagami, A West, T Yusufzai. Chromatin boundaries and chromatin domains. Cold Spring Harb Symp Quant Biol. 2004;69:245-250. T Ebersole, Y Okamoto, VN Noskov, N Kouprina, JH Kim, SH Leem, JC Barrett, H Masumoto, V Larionov. Rapid generation of long synthetic tandem repeats and its application for analysis in human artificial chromosome formation. Nucleic Acids Res. 2005 Sep 1;33(15):e130, doi:10.1093/nar/gni129. [PubMed abs] Patent Status: DHHS Reference No. E-154-2006/0 -- PCT Application No. PCT/US2008/054170 filed 15 Feb 2008, which published as WO 2008/101216 on 21 Aug 2008; claiming priority to 15 Feb 2007 Licensing Status: Available for exclusive or non-exclusive licensing. Collaborative Research Opportunity: The National Cancer Institute Laboratory of Molecular Pharmacology is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize gamma-satellite DNA insulators for stable transgene expression in ectopic chromosomal sites and in Human Artificial Chromosomes (HACs). Please contact John D. Hewes, Ph.D. at 301-435-3121 or hewesj@mail.nih.gov for more information. Portfolios: Gene-Based Therapies - Therapeutics, gene therapy, vectors, controlsequences/genes Gene-Based Therapies - Therapeutics, gene therapy, other Internal Medicine - Therapeutics, other For additional information, please contact: Sury Vepa, Ph.D. Office of Technology Transfer National Institutes of Health 6011 Executive Boulevard, Suite 325 Rockville MD 20852 Phone: 301/435-5020 Fax: 301/402-0220 Email: vepas@mail.nih.gov