Jagged1 is a competitive inhibitor of Notch signaling in the embryonic pancreas

Maria L. Golson, John Le Lay, Nan Gao, Nuria Brämswig, Kathleen M. Loomes, Rebecca Oakey, Catherine L. May, Peter White, Klaus H. Kaestner

Research output: Contribution to journalArticlepeer-review

Abstract

Pancreatic endocrine cells originate from precursors that express the transcription factor Neurogenin3 (Ngn3). Ngn3 expression is repressed by active Notch signaling. Accordingly, mice with Notch signaling pathway mutations display increased Ngn3 expression and endocrine cell lineage allocation. To determine how the Notch ligand Jagged1 (Jag1) functions during pancreas development, we deleted Jag1 in foregut endoderm and examined postnatal and embryonic endocrine cells and precursors. Postnatal Jag1 mutants display increased Ngn3 expression, α-cell mass, and endocrine cell percentage, similar to the early embryonic phenotype of Dll1 and Rbpj mutants. However, in sharp contrast to postnatal animals, Jag1-deficient embryos display increased expression of Notch transcriptional targets and decreased Ngn3 expression, resulting in reduced endocrine lineage allocation. Jag1 acts as an inhibitor of Notch signaling during embryonic pancreas development but an activator of Notch signaling postnatally. Expression of the Notch modifier Manic Fringe (Mfng) is limited to endocrine precursors, providing a possible explanation for the inhibition of Notch signaling by Jag1 during mid-gestation embryonic pancreas development.

Original languageEnglish (US)
Pages (from-to)687-699
Number of pages13
JournalMechanisms of Development
Volume126
Issue number8-9
DOIs
StatePublished - Aug 2009
Externally publishedYes

Keywords

  • Jagged1
  • Notch signaling
  • Pancreas development

ASJC Scopus subject areas

  • Embryology
  • Developmental Biology

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