Role of ERK1/2 signaling during EGF-induced inhibition of palatal fusion

Tadashi Yamamoto, Xiao Mei Cui, Charles F. Shuler

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

During mammalian palatal fusion, the medial edge epithelial (MEE) cells must stop DNA synthesis prior to the initial contact of opposing palatal shelves and thereafter selectively disappear from the midline. Exogenous EGF has been shown to inhibit the cessation of DNA synthesis and induce cleft palate; however, the precise intracellular mechanism has not been determined. We hypothesized that EGF signaling acting via ERK1/2 would maintain MEE DNA synthesis and cell proliferation and consequently inhibit the process of palatal fusion. Palatal shelves from E13 mouse embryos were maintained in organ cultures and stimulated with EGF. EGF-treated palates failed to fuse with intact MEE and had significant ERK1/2 phosphorylation. Both EGF-induced ERK1/2 phosphorylation and BrdU-incorporation were localized in the nucleus of MEE cells. Subsequent inhibition assays using U0126, a specific inhibitor of ERK1/2 phosphorylation, were conducted. U0126 inhibited EGF-induced ERK1/2 phosphorylation in a dose-dependent manner and consequently MEE cells stopped proliferation. The threshold of ERK1/2 inactivation to stop MEE DNA synthesis coincides with the level required to rescue the EGF-induced cleft palate phenotype. These results indicate that EGF-induced inhibition of palatal fusion is dependent on nuclear ERK1/2 activation and that this mechanism must be tightly regulated during normal palatal fusion.

Original languageEnglish
Pages (from-to)512-521
Number of pages10
JournalDevelopmental Biology
Volume260
Issue number2
DOIs
Publication statusPublished - Aug 15 2003
Externally publishedYes

Keywords

  • Cell proliferation
  • EGF
  • ERK1/2 signaling
  • Medial edge epithelium
  • Mouse
  • Organ culture
  • Palatogenesis

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

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