From the October Edition of Stem Cells
By Stuart P. Atkinson
The E-twenty six transcription factor, Elf5, has been previously identified as an important regulator of mammary alveolar development (Oakes et al and Choi et al). Elf5 is not expressed in the stem cell-enriched compartment of the mammary gland, but is expressed in both luminal progenitors and mature luminal cells and is required for the differentiation of luminal progenitor cells toward the alveolar lineage. Few studies have sought to understand the role of epigenetic regulation of gene expression in the mammary gland (Rinkels et al, Bloushtain-Qimron et al, Gu et al and Pietersen et al) and, as the epigenetic regulation of Elf itself is known to be very important during development (Ng et al), DNA methylation studies may allow a better understanding the epigenetic control of mammary development. This was the focus of a recent study published in the October edition of Stem Cells from the laboratories of Susan J. Clark and Christopher J. Ormandy at the Garvan Institute of Medical Research, New South Wales, Australia. Using bisulphite sequencing, the authors show that Elf5 expression and DNA methylation are correlated and so demonstrate that Elf5 promoter methylation is lineage-specific and developmentally regulated in the mammary gland in vivo (Lee and Hinshelwood et al).