Model for the initiation of differentiation through stage-specific Gata1 gene regulation. (A) In HSPCs, DNMT1 is recruited to the 3.2-kb sequence intervening the Gata1 gene enhancer sequences (red, G1HE; orange, double GATA sites; and blue, CACC box) and confers Gata1 gene inactivation by maintaining DNA methylation. GATA2 is unable to bind to the inactivated Gata1 gene. (B) Upon initiation of differentiation, DNA methylation decreases and GATA2 transactivates Gata1 gene expression. me, methylation.