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Mastermind critically regulates Notch-mediated lymphoid cell fate decisions
Ivan Maillard1, Andrew P Weng, Andrea C Carpenter
1Division of Hematology-Oncology, Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
Blood
|June 10, 2004
Summary
Mastermind-like proteins (MAMLs) are crucial for Notch signaling in vivo. A dominant-negative MAML1 mutant inhibited T-cell and marginal zone B-cell development, confirming MAMLs
Area of Science:
- Immunology
- Developmental Biology
- Molecular Biology
Background:
- Notch signaling is vital for lymphocyte development, regulating T-cell/B-cell fate and marginal zone B-cell (MZB) formation.
- Mastermind-like proteins (MAMLs) are known in vitro Notch coactivators, but their in vivo function remains unclear.
Purpose of the Study:
- To investigate the in vivo role of MAML proteins in hematopoietic development.
- To determine if MAMLs are essential for Notch-mediated cell fate decisions.
Main Methods:
- Introduction of a dominant-negative MAML1 (DNMAML1) mutant into murine hematopoietic stem cells.
- Analysis of T-cell and B-cell development following DNMAML1 transduction.
- Comparison of DNMAML1 effects with the Notch modulator Deltex1.
Main Results:
- DNMAML1 expression inhibited T-cell development and promoted intrathymic B-cell appearance, mimicking Notch1 inhibition.
- DNMAML1 significantly reduced MZB cell numbers, consistent with Notch2 inhibition.
- Deltex1 did not affect MZB cell numbers, unlike DNMAML1.
Conclusions:
- MAML proteins play a critical role in Notch-mediated cell fate decisions during hematopoiesis in vivo.
- DNMAML1 is a tool to inhibit multiple Notch family members, unlike Deltex1.