Tuesday, August 24, 2010

Prospects for the Use of Artificial Chromosomes and Minichromosome-Like Episomes in Gene Therapy

Journal of Biomedicine and Biotechnology, Volume 2010 (2010), Article ID 642804, 16 pages, doi:10.1155/2010/642804

Sara Pérez-Luz1,2,3 and Javier Díaz-Nido1,2,3

1Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain
2Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C/Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain
3U-748, Area de Neurogenética, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain

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Abstract

Artificial chromosomes and minichromosome-like episomes are large DNA molecules capable of containing whole genomic loci, and be maintained as nonintegrating, replicating molecules in proliferating human somatic cells. Authentic human artificial chromosomes are very difficult to engineer because of the difficulties associated with centromere structure, so they are not widely used for gene-therapy applications. However, OriP/EBNA1-based episomes, which they lack true centromeres, can be maintained stably in dividing cells as they bind to mitotic chromosomes and segregate into daughter cells. These episomes are more easily engineered than true human artificial chromosomes and can carry entire genes along with all their regulatory sequences. Thus, these constructs may facilitate the long-term persistence and physiological regulation of the expression of therapeutic genes, which is crucial for some gene therapy applications. In particular, they are promising vectors for gene therapy in inherited diseases that are caused by recessive mutations, for example haemophilia A and Friedreich's ataxia. Interestingly, the episome carrying the frataxin gene (deficient in Friedreich's ataxia) has been demonstrated to rescue the susceptibility to oxidative stress which is typical of fibroblasts from Friedreich's ataxia patients. This provides evidence of their potential to treat genetic diseases linked to recessive mutations through gene therapy.

Section: "4.4. Gene Therapy for Friedreich’s Ataxia"

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Mitochondrial protein import: from proteomics to functional mechanisms

Nature Reviews Molecular Cell Biology 11, 655–667 (1 September 2010) | doi:10.1038/nrm2959

Oliver Schmidt , Nikolaus Pfanner & Chris Meisinger

Keywords: Mitochondria, proteins, cytosol, import pathways, protein translocases.