Serial bone marrow transplantation reveals in vivo expression of the pCLPG retroviral vector | Fratini and Strauss Virology Journal 2010 7 16 http content 7 1 16 VIROLOGY JOURNAL RESEARCH Open Access Serial bone marrow transplantation reveals in vivo expression of the pCLPG retroviral vector Paula Fratini1 2 3 Bryan E Strauss1 2 3 Abstract Background Gene therapy in the hematopoietic system remains promising though certain aspects of vector design such as transcriptional control elements continue to be studied. Our group has developed a retroviral vector where transgene expression is controlled by p53 with the intention of harnessing the dynamic and inducible nature of this tumor suppressor and transcription factor. We present here a test of in vivo expression provided by the p53-responsive vector pCLPG. For this we used a model of serial transplantation of transduced bone marrow cells. Results We observed by flow cytometry that the eGFP transgene was expressed at higher levels when the pCLPG vector was used as compared to the parental pCL retrovirus where expression is directed by the native MoMLV LTR. Expression from the pCLPG vector was longer lasting but did decay along with each sequential transplant. The detection of eGFP-positive cells containing either vector was successful only in the bone marrow compartment and was not observed in peripheral blood spleen or thymus. Conclusions These findings indicate that the p53-responsive pCLPG retrovirus did offer expression in vivo and at a level that surpassed the non-modified parental pCL vector. Our results indicate that the pCLPG platform may provide some advantages when applied in the hematopoietic system. Background The merits and shortcomings related to the use of retroviral vectors for laboratory and clinical gene transfer have been intensely studied. Vectors derived from the Moloney Murine Leukemia Virus MoMLV hold an important historical place in the development of clinical gene therapy. These vectors are relatively easy to produce and manipulate are quite malleable and are extremely
