EXPRESSION VECTORS COMPRISING CHIMERIC CYTOMEGALOVIRUS PROMOTER AND ENHANCER SEQUENCES

The present invention relates to expression vectors for the heterologous expression of a nucleic acid sequence of interest in mammalian cells, the vectors comprising a chimeric promoter regulatory sequence being operably linked to a nucleic acid sequence to be expressed, wherein the chimeric promoter regulatory sequence comprises a cytomegalovirus promoter sequence derived from murine cytomegalovirus and being operably linked to the transcriptional start site of the nucleic acid sequence to be expressed; and a cytomegalovirus upstream region and/or enhancer sequence derived from human and/or the simian cytomegalovirus, wherein the upstream region and/or enhancer sequence is located 5' of the murine promoter sequence. In particular embodiments, the chimeric promoter regulatory sequence comprises sequence elements derived from the murine cytomegalovirus IE1 promoter and from the human and/or the simian cytomegalovirus IE1 region. The invention also relates to mammalian host cells transfected with such expression vectors, a method for heterologous expression of a nucleic acid sequence in a mammalian host cell by employing such expression vectors, and the use of such expression vectors for the heterologous expression of a nucleic acid sequence.