Illustration of the human HNRPA2B1-CBX3-NFE2L3 locus and derivation of the A2UCOE. (A, top panel) Gene organization of the HNRPA2B1-CBX3-NFE2L3 locus located at chromosome position 7p15.2 (GenBank accession nos. D28877, AC004520, and AC010677) is shown with gene positions indicated (shaded rectangles). (Bottom panel) Expanded view of the 3-kb methylation-free CpG island region encompassing the divergent CBX3 and HNRPA2B1 promoters. The region covered by the minimal 2.2-kb UCOE (A2UCOE; M.A. et al²⁹ ) extending from the TthIII I (T) site within exon I of HNRPA2B1 to a BamHI (B) site within the first intron of CBX3 is shown. Black rectangles denote exons. Horizontal arrows denote the direction of transcription. (B) Illustration of the lentiviral vector constructs. LTR indicates long-terminal repeat; RRE, rev-response element; Ψ, packaging signal; RSV, Rous sarcoma virus U3; and PRE, mutated Woodchuck hepatitis posttranscriptional regulatory element.