Changes in CpG methylation marks differentiation of human myeloid progenitors to neutrophils

The role of CpG methylation in the silencing of cancercausing genes was established more than a decade ago (1). Yet, the role of CpG methylation in normal cellular differentiation is only beginning to be understood. Studies performed over the last 5 years have detailed essential changes of CpG methylation during mouse granulopoiesis (2,3). A recent article in Blood by Rönnerblad et al. (4), has added substantially to these data, showing temporal DNA methylation during human granulopoiesis regulates the expression of key genes including transcription factors.