In an effort to improve product yield of mammalian cell lines, we have previously demonstrated that our proprietary DNA elements, Selexis Genetic Elements (SGEs), increase the transcription of a given transgene1, thus boosting the overall expression of a therapeutic protein drug in mammalian cells. However, there are additional cellular bottlenecks, notably in the molecular machineries of the secretory pathways. Most importantly, mammalian cells have some limitations in their intrinsic capacity to manage high level of protein synthesis as well as folding recombinant proteins. These bottlenecks often lead to increased cellular stress and, therefore, low production rates. Our specific approach involves CHO cell line engineering. We constructed a CHO-M library based upon the CHO-M genome and transcriptome and using unique proprietary transposon vectors harboring SGE DNA elements to compensate for rate-limiting factors. This CHO-Mplus library displays a diversity of greater than 1×107 auxiliary proteins involved in secretory pathway machineries and cellular metabolism. We show that our CHO-Mplus library enabled the selection of a clonal cell line expressing 10 fold more product by comparison to standard approaches.