An experimentally tractable system for investigating cell-fate determination in plants is the specification of the predictable pattern of hair and non-hair cells seen in the Arabidopsis root epidermis. Several putative transcriptional regulators have been implicated in this process and, on p. 6431, Bernhardt et al. report that two Arabidopsis genes encoding basic helix-loop-helix proteins - GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3) - act in a partly redundant manner during the specification of root epidermal cells. No non-hair cells were formed in plants carrying homozygous null mutations in both genes. Conversely, overexpression of either gene produced ectopic non-hair cells. Other results indicate that GL3/EGL3 also influence hair cell specification,leading the researchers to propose a model in which interactions between GL3/EGL3 and the MYB proteins WEREWOLF and CAPRICE mediate cell-fate decision during the development of the root epidermis.