Placing the RPL32 Promoter Upstream of a Second Promoter Results in a Strongly Increased Number of Stably Transfected Mammalian Cell Lines That Display High Protein Expression Levels

<table>Heterologous promoters that are screened for their ability to elevate the formation of stable CHO-DG44 colonies in the context of a stringent selection system. Twelve human promoters were placed upstream of the human <i>β</i>-actin promoter. As selection system, a modified Zeocin selection marker, TTG Zeocin was placed upstream of the d2EGFP reporter gene. As control constructs, either no DNA elements are incorporated to the construct, or STAR elements are added to flank the expression cassette. Equal amounts of DNA were transfected to CHO-DG44 and after ~two weeks colonies were counted.</table>

Biotechnology Research International

fig1

Figure 1

Figure 1: Placing the RPL32 Promoter Upstream of a Second Promoter Results in a Strongly Increased Number of Stably Transfected Mammalian Cell Lines That Display High Protein Expression Levels 

Figure 1 | Placing the RPL32 Promoter Upstream of a Second Promoter Results in a Strongly Increased Number of Stably Transfected Mammalian Cell Lines That Display High Protein Expression Levels 