pLPCX contains elements derived from Moloney murine leukemia virus (MoMuLV) and Moloney murine sarcoma virus(MoMuSV), and is designed for retroviral gene delivery and expression. Upon transfection into a packaging cell line, pLPCX transiently expresses, or integrates and stably expresses, a transcript containing Ψ+ signal) the puromycin resistance gene, and the gene of interest. The 5' viral LTR in this vector contains promoter/enhancer sequences that control expression of the puromycin resistance(Puro+) gene for antibiotic selection in eukaryotic cells. A gene of interest can be cloned into the multiple cloning site immediately downstream of the human cytomegalovirus (CMV) immediate early promoter. pLPCX also includes the Col E1 origin of replication and E.coli Amp+ gene for propagation and antibiotic selection in bacteria.