The invention relates to an expression vector comprising at least those components of the vectors pBR322 or pKK223-3, necessary for the replication thereof, an expression region sequentially comprising, in the reading direction, a first promotor, a binding site specific for a repressor, a sequence corresponding to a prokaryotic ribosome binding site, a cloning site with a gene coding for annexin V, at least one transcription terminator and at least one kanamycin-resistant gene with a second promotor.