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Blood, 15 February 2008, Vol. 111, No. 4, pp. 1866-1875. Prepublished online as a Blood First Edition Paper on November 8, 2007; DOI 10.1182/blood-2007-04-085506. This Article Full Text Full Text (PDF) Supplemental Methods, Tables, and Figures All Versions of this Article: blood-2007-04-085506v1 111/4/1866    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Google Scholar Articles by Ryu, B. Y. Articles by Nienhuis, A. W. PubMed PubMed Citation Articles by Ryu, B. Y. Articles by Nienhuis, A. W. Related Collections Gene Therapy Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  GENE THERAPY An experimental system for the evaluation of retroviral vector design to diminish the risk for proto-oncogene activation Byoung Y. Ryu1, Marguerite V. Evans-Galea1, John T. Gray1, David M. Bodine2, Derek A. Persons1, and Arthur W. Nienhuis1 1 Department of Hematology, St Jude Children's Research Hospital, Memphis, TN; and 2 Genetics and Molecular Biology Branch, National Human Genome Research Institute, Bethesda, MD Pathogenic activation of the LMO2 proto-oncogene by an oncoretroviral vector insertion in a clinical trial for X-linked severe combined immunodeficiency (X-SCID) has prompted safety concerns. We used an adeno-associated virus vector to achieve targeted insertion of a -retroviral long terminal repeat (LTR) driving a GFP expression cassette with flanking loxP sites in a human T-cell line at the precise location of vector integration in one of the patients with X-SCID. The LTR-GFP cassette was inserted into the first intron of the LMO2 gene, resulting in strong activation of LMO2. Cre-mediated cassette exchange was used to replace the original LTR-GFP cassette with one flanked by insulator elements leading to a several fold reduction in LMO2 expression. The LTR-GFP cassette was also replaced with a globin gene regulatory cassette that failed to activate the LMO2 gene in lymphoid cells. A -retroviral vector with 2 intact LTRs resulted in activation of the LMO2 gene when inserted into the first intron, but a self-inactivating lentiviral vector with an internal cellular promoter and flanking insulator elements did not activate the LMO2 gene. Thus, this system is useful for comparing the safety profiles of vector cassettes with various regulatory elements for their potential for proto-oncogene activation. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Intentionally integrating in oncogenes David W. Russell Blood 2008 111: 1754. [Full Text] [PDF] This article has been cited by other articles: A. W. Nienhuis Development of gene therapy for blood disorders Blood, May 1, 2008; 111(9): 4431 - 4444. [Abstract] [Full Text] [PDF]

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