Pax5/BSAP maintains the identity of B cells in late B lymphopoiesis.
The B lineage commitment factor Pax5 (BSAP) is expressed throughout B cell development. To investigate its late function, we generated a mouse strain carrying a floxed Pax5 allele that was conditionally inactivated by CD19-cre or Mx-cre expression. Pax5 deletion resulted in the preferential loss of mature B cells, inefficient lymphoblast formation, and reduced serum IgG levels. Mature B cells radically changed their gene expression pattern in response to Pax5 inactivation. Most B cell antigens were downregulated on the cell surface, and the transcription of B cell-specific genes was decreased, whereas the expression of non-B lymphoid genes was activated in Pax5-deficient B cells. These data demonstrate that Pax5 is essential for maintaining the identity and function of B cells during late B lymphopoiesis.
Horcher
M
M
Research Institute of Molecular Pathology, Vienna Biocenter, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria.
Souabni
A
A
Busslinger
M
M
D000483:Alleles; D000818:Animals; D018941:Antigens, CD19 / Q000276:immunology; D000954:Antigens, Surface / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D005091:Exons; D020869:Gene Expression Profiling; D007072:Immunoglobulin D / Q000096:biosynthesis; D007074:Immunoglobulin G; D019426:Integrases; D019891:Leukopoiesis; D051379:Mice; D008810:Mice, Inbred C57BL; D051757:PAX5 Transcription Factor; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors; D014764:Viral Proteins
D018941:Antigens, CD19; D000954:Antigens, Surface; D004268:DNA-Binding Proteins; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D051757:PAX5 Transcription Factor; C497282:Pax5 protein, mouse; D011506:Proteins; D014157:Transcription Factors; D014764:Viral Proteins; C045073:Cre recombinase; D019426:Integrases