Fig. 3
Screening of Kozak variants with stronger GFP expression strength in comparison to the original UASF-E-C-Core1 artificial promoter. A Comparison of the strength of 14 Kozak variants obtained by two rounds of GFP fluorescence screening to the starting UASF-E-C-Core1 promoter. The known strong promoter PTDH3 was used as a positive control. B The 5′UTR sequences of the 14 chimeric promoters and the Kozak sequences are underlined. C The consensus patterns of Kozak sequence alignments were visualized using the WebLogo 3 tool (http://weblogo.threeplusone.com/create.cgi) with default settings. D Analysis of mRNA secondary structures for the K0, K540, K536, and K528 variants using the RNAfold server (http://rna.tbi.univie.ac.at//cgi-bin/RNAWebSuite/RNAfold.cgi). The results were represented by a mountain plot which shows the MFE structure (red line), the thermodynamic ensemble of RNA structures (green line), and the centroid structure (blue line), as well as the positional entropy for each position