Deciphering the Cross Talk of Transcription Factors and the Epigenome in Epithelial to Mesenchymal Transition
Epithelial-to-mesenchymal transition (EMT) is a fundamental process that is widely employed during development, including during gastrulation, neural crest migration, and cortical development. EMT is also important in wound healing and pathological conditions such as cancer metastasis and organ fibrosis. Lavin et al. (e00183-21) provide a comprehensive study investigating the kinetics and potential function of many basic helix-loop-helix (bHLH) transcription factors during EMT in mammary epithelial cells. They show that Mnt is induced during EMT and is essential for the process. Mnt promotes EMT by recruiting histone deacetylase 1 and repressing target genes underlying epithelial identity via epigenetic mechanisms.
A New Mouse Model for Identifying Regulators of HO-1 Gene Expression
Heme oxygenase 1 (HO-1) is the key enzyme in the heme catabolic pathway and plays critical roles in various cytoprotective responses. Zhang et al. (e00236-21) established an HO-1–DsRed knock-in reporter mouse to monitor HO-1 expression in the whole body in vivo and ex vivo. Analyses of peritoneal macrophages from HO-1–DsRed mice lacking NRF2, a major regulator of the oxidative/electrophilic stress response, identified two distinct types of HO-1 induction: NRF2-dependent stress response-mediated induction and substrate heme-mediated but NRF2-independent induction. Thus, the authors provide a useful model system for monitoring HO-1 gene expression and demonstrate two distinct levels of HO-1 gene regulation.