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Regulation of Promoter and Intron Enhancer Activity in Immunoglobulin Heavy‐Chain Genes during B‐Cell Differentiation
Author(s) -
Naito Akihiro,
Suzuki Yasuhiko,
Azuma Takachika
Publication year - 1998
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1998.tb02301.x
Subject(s) - enhancer , biology , immunoglobulin heavy chain , intron , gene , antibody , genetics , immunoglobulin light chain , b cell , microbiology and biotechnology , gene expression
Chloramphenicol acetyltransferase (CAT) transgenic mice, in which the transgene is regulated by the VH promoter and heavy‐chain intron enhancer (Eμ), were examined to investigate the variation of activity of these cis‐acting elements during the late stage of B‐cell development. CAT enzyme activity decreased when resting B cells were stimulated through B‐cell receptors (BCR) with goat anti‐mouse IgM antibodies in vitro . On the other hand, when these B cells were stimulated by lipopolysaccharide (LPS) in vitro , they showed enhanced CAT activity, accompanied by an increase in the number of CD43 + B220 + cells (pro‐plasma and plasma cells). In addition, the CAT activities in CD43 + B220 + and PNA hi B220 + cells from immunized mice were higher than those in CD43 − B220 + and PNA lo B220 + cells, respectively. These results suggest that the activity of Eμ in the context of VH promoter was transiently down‐regulated by stimulation through the BCR but enhanced at the pro‐plasma and plasma stages.