c-Myb is critical for B cell development and maintenance of follicular B cells

Matthew D Thomas1, Christopher S Kremer, Kodi S Ravichandran

  • 1Department of Microbiology, P.O. Box 800734, University of Virginia Health System, Charlottesville, VA 22908, USA.

Immunity
|September 20, 2005
PubMed

The c-Myb transcription factor is crucial during definitive hematopoiesis. However, the embryonic lethality of Myb traditional null mutations has precluded analysis of c-Myb function in lymphocytes. Using tissue-specific inactivation at the Myb locus, we demonstrate that loss of Myb causes a partial block during B cell development at the pro-B to pre-B cell transition, resulting in greatly decreased output of new B cells from the bone marrow. Furthermore, we demonstrate that Myb is not essential for the proliferation of splenic B cells, but that loss of c-Myb function prevents normal B cell homeostasis due to decreased splenic B cell survival. Decreased survival is accompanied by hyporesponsiveness to the B cell survival factor BLyS (also termed BAFF), decreased expression of the BLyS receptor 3 (BR3), and altered regulation of PKCdelta nuclear accumulation. Thus, c-Myb is important during multiple stages of B-lymphopoiesis.

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