Figure 4. Human HT1080 cells carrying the 21HAC2 and tet-O HAC2 vectors expressing the EGFP and DsRed genes.
(a) Scheme of transferring the EGFP-21HAC2 and tet-O-DsRed-HAC2 vectors and elimination of the tet-O-DsRed-HAC2 vector after expression of the tTS gene. (b) FISH analysis of the HT72 cells carrying EGFP-21HAC2 and tet-O-DsRed-HAC2 vectors. FISH analysis was performed using a biotin-labeled probe for the DsRed gene (green) and digoxigenin-labeled p11-4 (a hChr.21-derived α-satellite clone) (red). (c) Bright-field and fluorescence images of HT72 cells after elimination of the tet-O-DsRed-HAC2 vector. (d) FACS analysis was performed to detect the EGFP and DsRed genes expression 7 days after introduction of the tTS gene. (e) The retention rate of the EGFP-21HAC2 and tet-O-DsRed-HAC2 vectors was calculated by FISH analysis 7 days after introduction of the tTS gene. 200 interphase were counted for calculating the retention rate of HACs.