Complete block of early B cell differentiation and altered patterning of the posterior midbrain in mice lacking Pax5/BSAP

Cell. 1994 Dec 2;79(5):901-12. doi: 10.1016/0092-8674(94)90079-5.


The Pax5 gene, coding for the transcription factor BSAP, was mutated in the mouse germline by targeted disruption. Homozygous mutant mice were born alive, became growth retarded, and usually died within three weeks. About 5% of mutants survived to adulthood and were fertile, but severely runted. Morphogenesis of the posterior midbrain was affected as early as embryonic day 16.5, leading to a reduction of the inferior colliculus near the midline and to altered foliation of the anterior cerebellum. Moreover, all mutants failed to produce small pre-B, B, and plasma cells owing to a complete arrest of B cell development at an early precursor stage. These data define a key role for Pax5 in early B lymphopoiesis and midbrain patterning.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / physiology*
  • Base Sequence
  • Behavior, Animal
  • Brain / abnormalities
  • Brain / embryology*
  • Cell Differentiation
  • Cerebellum / abnormalities
  • Cerebellum / embryology
  • DNA-Binding Proteins / genetics*
  • Genes, Lethal
  • Hematopoiesis / genetics*
  • Homozygote
  • IgG Deficiency / blood
  • Lymphoid Tissue / abnormalities
  • Mesencephalon / abnormalities
  • Mesencephalon / embryology
  • Mice
  • Mice, Mutant Strains
  • Molecular Sequence Data
  • Nuclear Proteins / genetics*
  • PAX5 Transcription Factor
  • Reflex
  • Transcription Factors / genetics*


  • DNA-Binding Proteins
  • Nuclear Proteins
  • PAX5 Transcription Factor
  • Pax5 protein, mouse
  • Transcription Factors