Engrailed-1 Promotes Eccrine Sweat Gland Development in Permissive Environments

The 2016 study "706 Engrailed-1 promotes eccrine sweat gland development in permissive environments" found that the Engrailed-1 (En1) gene, a homeodomain transcription factor, plays a significant role in the development of eccrine sweat glands in mice. The researchers discovered that the relative frequency of eccrine glands and hair follicles is fixed within inbred strains and varies between them. They used QTL analysis to identify a small number of loci that explain much of this variation, with En1 lying within the strongest of these QTLs. Reduction of En1 gene dosage was shown to reduce the frequency of eccrine glands within both test strains in the QTL cross, suggesting that En1 levels in the plantar epidermis directly alter appendage fate. Further tests confirmed that increased En1 expression in the epidermis increases the relative density of eccrine glands and that higher En1 levels can convert the entire population of cutaneous appendages in the region to eccrine sweat glands.