Figure 1 | Scientific Reports

Figure 1

From: An efficient protein production system via gene amplification on a human artificial chromosome and the chromosome transfer to CHO cells

Figure 1

Schematic diagram of the IR/MAR HAC gene amplification system. (A) Step 1: HAC vector transfer from CHO K1 cells into CHO DG44 cells. Step 2: Multimerization of MAR vector and insertion of target genes into HAC. Step 3: Analysis of the effect of gene amplification on the gene expression level. The EGFP loxP MAR vector includes the CAG promoter to drive expression of EGFP cDNA, the IR/MAR sequence, and the loxP site. The EGFP loxP vector includes only the CAG promoter to drive EGFP cDNA and the loxP site as a control. Cre indicates use of the Cre recombinase for Cre-loxP site-specific recombination. (B) Multi-color FISH analysis in CHO K1 cells. The three large metacentric chromosomes (indicated by the arrows) characterize the karyotype of CHO K1 cells. (C) Multi-color FISH analysis in CHO DG44 cells. The two large metacentric chromosomes (indicated by the arrows) characterize the karyotype of CHO DG44 cells. (D) FISH analysis with a digoxigenin-labeled hCot-1 DNA (red) identified the HAC vector in CHO K1 cells (indicated by the arrowhead). The inset shows enlarged images of the HAC. The arrows indicate the three large metacentric chromosomes, which identify CHO K1 cells. (E) FISH analysis with a digoxigenin-labeled hCot-1 DNA (red) identified the HAC vector in CHO DG44 cells (indicated by the arrowhead). The inset shows enlarged images of the HAC. The arrows indicate two large metacentric chromosomes that identify CHO DG44 cells.

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