DNA MOLECULE COMPRISING A POLYCISTRONIC TRANSCRIPTION UNIT COMPRISING A NON-OPTIMAL START CODON FOR A SELECTION MARKER

摘要

Title: Selection of host cells expressing protein at high levels Abstract The invention provides a DNA molecule comprising a 5 multicistronic transcription unit coding for i) a selectable marker polypeptide functional in a eukaryotic host cell, and for ii) a polypeptide of interest, the polypeptide of interest having a translation initiation sequence separate from that of the selectable 10 marker polypeptide, characterized in that the coding sequence for the polypeptide of interest is downstream from the coding sequence for the selectable marker in said multicistronic transcription unit, and the nucleic acid sequence coding for the selectable marker 15 polypeptide comprises a mutation that decreases the translation efficiency of the selectable marker in a eukaryotic host cell. The invention also provides methods for obtaining host cells expressing a polypeptide of interest, said host cells comprising the DNA molecules of 20 the invention. The invention further provides the production of polypeptides of interest, comprising culturing host cells comprising the DNA molecules according to the invention.