The ability of eukaryotic ribosomes to reinitiate translation at downstream AUG codons on polycistronic mRNAs was used to select transfected CHO clones that secreted a precursor to the human pancreatic poly-peptide (PP). In the in vitro constructed transcription unit, a viral promoter directed the synthesis of a dicistronic mRNA. The PP cDNA was placed in the 5′-part of this transcript, while a DHFR cDNA was placed 3′ to the PP. This dicistronic expression unit was transfected into CHO cells, and methotrexate-resistant colonies were selected. RNA-blots verified that the PP precursor and DHFR were expressed from the same dicistronic mRNA. The CHO cells synthesized the hormone precursor and secreted it through the constitutive secretory pathway. © 1987.
Boel, E., Berkner, K. L., Nexø, B. A., & Schwartz, T. W. (1987). Expression of human pancreatic polypeptide precursors from a dicistronic mRNA in mammalian cells. FEBS Letters, 219(1), 181–188. https://doi.org/10.1016/0014-5793(87)81213-9