Grainyhead-like 2 regulates neural tube closure and adhesion molecule expression during neural fold fusion

Abstract

Summary Defects in closure of embryonic tissues such as the neural tube, body wall, face and eye lead to severe birth defects. Cell adhesion is hypothesized to contribute to closure of the neural tube and body wall, however potential molecular regulators of this process have not been identified. Here we identify an ENU-induced mutation in mice that reveals a molecular pathway of embryonic closure. Line2F homozygous mutant embryos fail to close the neural tube, body wall, face, and optic fissure, and they also display defects in lung and heart development. Using a new technology of genomic sequence capture and high-throughput sequencing of a 2.5 Mb region of the mouse genome, we discovered a mutation in the grainyhead-like 2 gene (Grhl2). Microarray analysis revealed Grhl2 affects the expression of a battery of genes involved in cell adhesion and E-cadherin protein is drastically reduced in tissues that require Grhl2 function. The tissue closure defects in Grhl2 mutants are similar to that of AP-2α null mutants and AP-2α has been shown to bind to the promoter of E-cadherin. Therefore, we tested for a possible interaction between these genes. However, we find that Grhl2 and AP-2α do not regulate each other’s expression, E-cadherin expression is normal in AP-2α mutants during neural tube closure, and Grhl2;AP-2α trans-heterozygous embryos are morphologically normal. Taken together, our studies point to a complex regulation of neural tube fusion and highlight the importance of comparisons between these two models to understand more fully the molecular pathways of embryonic tissue closure.

Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium

“…In the embryonic mouse lung, Grhl1-3 genes exhibit differential spatiotemporal patterns of expression in the epithelium (15,16). Recent analysis of Grhl2 mutants, which die around embryonic day 11.5 from neural tube closure defects, indicates that the gene plays a role in lung branching morphogenesis (17). In addition, recent studies with mouse lung alveolar-like cell lines in culture strongly support a role for Grhl2 in cell adhesion, motility, and junction formation and identify a number of likely primary targets (16).…”

Downregulation of GRHL2 inhibits the proliferation of colorectal cancer cells by targeting ZEB1

“…4,5 This protein expressed in epithelial structures acts as a transcriptional activator, regulating epidermal development. 6,7 GRHL2 is associated with age-related hearing impairment, 8 neural tube closure, 9 epidermal integrity, 10 wound healing, 11 and the regulation of many physiological functions of human airway epithelium. 12 In the context of cancer, GRHL2 has been reported to function as a tumor suppressor.…”

A Grainyhead-Like 2/Ovo-Like 2 Pathway Regulates Renal Epithelial Barrier Function and Lumen Expansion

“…8 Grhl2 is required for important morphogenetic events during embryonic development, with gene deletion in mice leading to defective neural tube closure, split face malformations, exencephaly, and death at embryonic day (E) 11.5. [8][9][10] Grhl2 was reported to participate in epithelial morphogenesis and differentiation in cultured airway, 11 in biliary and hepatic epithelia, 12,13 and in tumorigenesis of skin and mammary epithelial cells. 14,15 However, the underlying genetic networks are incompletely understood.…”