Synergism between NF-kappa B1/p50 and Notch2 during the development of marginal zone B lymphocytes.

NF-kappaB1 and Notch2 are both required for the development of marginal zone (MZ) B cells. Analysis of B lymphocyte development in mice that are doubly heterozygous at the Notch2 and NF-kappaB1 loci revealed synergism between Notch2 and NF-kappaB1 during MZ B cell development. Two known transcriptional targets of the Notch pathway, Hes-5 and Deltex-1, were found to be preferentially expressed in MZ B cells and regulated by NF-kappaB1. These studies provide in vivo evidence for a genetic interaction between the Notch and NF-kappaB pathways.