FMEV VECTORS - BOTH RETROVIRAL LONG TERMINAL REPEAT AND LEADER ARE IMPORTANT FOR HIGH EXPRESSION IN TRANSDUCED HEMATOPOIETIC-CELLS

FMEV retroviral the long terminal repeat of Friend mink cell focus-for ming viruses with the 5' untranslated leader region of the murine embr yonic stem cells virus. These modules were connected to achieve high t ransgene expression in hematopoietic progenitor and stem cells. Here, we report the cloning of safety-improved and versatile FMEV vectors al lowing module-wise exchange of crucial elements for for comparative st udies. By transfer and expression of four different marker genes (neom ycin phosphotransferase, lacZ, enhanced green fluorescent protein and truncated low affinity nerve growth factor receptor), we formally demo nstrate that both the long terminal repeat and the leader contribute t o the high I expression of FMEV in transduced hematopoietic cells.; Mo st prominent are the data recorded in the absence of selection in myel o-erythroid progenitor cells. Here, FMEV vectors mediate up to two ord ers of magnitude increased I transgene expression levels when compared with vectors I based on the Moloney murine leukemia virus.