The lymphoid-specific cofactor OBF-1 is essential for the expression of a V-H promoter/HS1,2 enhancer-linked transgene in late B cell development

Mice deficient for the lymphoid-specific cofactor OBF-1 display reduced lev els of IgG, IgA and IgE. To examine whether the lowered immunoglobulin expr ession is linked to reduced activity of IgH cis-regulatory elements, OBF-1( -/-) mice were crossed with mice expressing transgenes driven by a V-H or b eta -globin promoter linked to the HS1,2 enhancer. Here we show that OBF-1 is essential for the induced expression of a V-H promoter-linked transgene, in contrast to a beta -globin promoter-dependent transgene, in LPS/IL-4 or CD40-stimulated splenic B cells. Furthermore, impaired transgene expressio n is observed in OBF-1(-/-) peritoneal B cells. This deficiency may be link ed to OBF-1, as peritoneal cells from normal mice express OBF-1 protein con stitutively. Our data link OBF-1 to IgH gene expression in late B lymphoid development. (C) 2001 Elsevier Science Ltd. All rights reserved.