Abstract
During early pancreatic development, Notch signaling represses differentiation of endocrine cells and promotes proliferation of Nkx6-1 +Ptf1a+ multipotent progenitor cells (MPCs). Later, antagonistic interactions between Nkx6 transcription factors and Ptf1a function to segregate MPCs into distal Nkx6-1-Ptf1a+ acinar progenitors and proximal Nkx6-1+Ptf1a- duct and β-cell progenitors. Distal cells are initially multipotent, but evolve into unipotent, acinar cell progenitors. Conversely, proximal cells are bipotent and give rise to duct cells and late-born endocrine cells, including the insulin producing β-cells. However, signals that regulate proximodistal (P-D) patterning and thus formation of β-cell progenitors are unknown. Here we show that Mind bomb 1 (Mib1) is required for correct P-D patterning of the developing pancreas and β-cell formation. We found that endoderm-specific inactivation of Mib1 caused a loss of Nkx6-1+Ptf1a- and Hnf1β+ cells and a corresponding loss of Neurog3+ endocrine progenitors and β-cells. An accompanying increase in Nkx6-1 -Ptf1a+ and amylase+ cells, occupying the proximal domain, suggests that proximal cells adopt a distal fate in the absence of Mib1 activity. Impeding Notch-mediated transcriptional activation by conditional expression of dominant negative Mastermind-like 1 (Maml1) resulted in a similarly distorted P-D patterning and suppressed β-cell formation, as did conditional inactivation of the Notch target gene Hes1. Our results reveal iterative use of Notch in pancreatic development to ensure correct P-D patterning and adequate β-cell formation.
Original language | English |
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Journal | Proceedings of the National Academy of Sciences USA (PNAS) |
Volume | 109 |
Issue number | 19 |
Pages (from-to) | 7356-61 |
Number of pages | 6 |
ISSN | 0027-8424 |
DOIs | |
Publication status | Published - 8 May 2012 |
Keywords
- Animals
- Basic Helix-Loop-Helix Transcription Factors
- Blotting, Western
- Cell Lineage
- Embryo, Mammalian
- Female
- Gene Expression Regulation, Developmental
- Hepatocyte Nuclear Factor 1-beta
- Hepatocyte Nuclear Factor 3-beta
- Homeodomain Proteins
- Insulin-Secreting Cells
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Mutation
- Nerve Tissue Proteins
- Nuclear Proteins
- Pancreas
- Receptors, Notch
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Time Factors
- Transcription Factors
- Ubiquitin-Protein Ligases