Transgene Copy Number – Impact on Clone Performance

Transcription rate as a key factor determining productivity of a cell line is a function of promoter strength and accessibility as well as the number of expression units. This simple logic was the rationale for gene amplification strategies that have been applied extensively in the past but lost attractivity mainly due to substantial time requirements. However, multiple copies are not limited to gene amplification. Transfection techniques such as calcium phosphate co-precipitation, PEI transfection and even electroporation result in multicopy integrates without the stepwise increase of selection pressure that induce amplification.