Figure 1From: DNA fragments binding CTCF in vitro and in vivo are capable of blocking enhancer activityPlasmid constructions used in this work. mPGK-1-mouse phosphoglycerate kinase I promoter; NeoR-E. coli neomycin phosphotransferase gene; HSV-tk-herpes simplex virus thymidine kinase gene. Broken arrows indicate direction of transcription. For detailed description, see the text.Back to article page