MYRF restrains mesothelial plasticity to protect the lung.

In this issue of Developmental Cell, Luna et al.1 identify myelin regulatory factor (MYRF) as a critical determinant of lung mesothelial specification and quiescence. Their study demonstrates that MYRF loss leads to congenital diaphragmatic hernia or a pleuroparenchymal fibroelastosis-like phenotype, revealing the mesothelium as an actively restrained progenitor population.