Evidence that the mouse 3' kappa light chain enhancer confers position-independent transgene expression in T- and B-lineage cells.
One of the major obstacles for successful application of murine leukemia virus (MLV) vectors to genetic therapy of lymphocyte disorders is low levels of transgene expression or the eventual loss of expression. To overcome this problem, an improved retroviral vector was constructed utilizing the myeloproliferative sarcoma virus (MPSV) long terminal repeat (LTR), which provided a significantly higher level of transgene expression in human lymphoid cells than did MLV vectors. Nevertheless, transgene expression remained low in a large percentage of transduced cells. To address whether lymphocyte enhancer elements might improve transgene expression mediated by retroviral vectors in lymphocytes, we cloned the mouse immunoglobulin 3' kappa light chain enhancer gene (mE3') into the MPSV vector. We found that the mE3' conferred a higher, more uniform and sustained level of expression in transduced T- and B-cell lines, and in primary T cells, than did the control vector lacking this element. Integration sites were diverse and a single copy of the proviral genome was present in all examined transduced cells. The mE3' failed to enhance transgene expression in most nonlymphoid cells, indicating it is relatively lineage-specific. Taken together, these results provide strong evidence that the mE3' functions as a locus control region (LCR) in conferring enhanced integration-site-independent expression of a retroviral transgene.
Xu
Lai
L
Division of Therapeutic Proteins, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
Tsuji
Kazuhide
K
Mostowski
Howard
H
Candotti
Fabio
F
Rosenberg
Amy
A
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D003001:Cloning, Molecular; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D051379:Mice; D012190:Retroviridae / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology; D019076:Transgenes
D007145:Immunoglobulin kappa-Chains