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ARTICLE |
B activity marks cells engaged in receptor editing
CORRESPONDENCE Mark S. Schlissel: mss{at}berkeley.edu
Because of the extreme diversity in immunoglobulin genes, tolerance mechanisms are necessary to ensure that B cells do not respond to self-antigens. One such tolerance mechanism is called receptor editing. If the B cell receptor (BCR) on an immature B cell recognizes self-antigen, it is down-regulated from the cell surface, and light chain gene rearrangement continues in an attempt to edit the autoreactive specificity. Analysis of a heterozygous mutant mouse in which the NF-
B–dependent I
B
gene was replaced with a lacZ (β-gal) reporter complementary DNA (cDNA; I
B
+/lacZ) suggests a potential role for NF-
B in receptor editing. Sorted β-gal+ pre–B cells showed increased levels of various markers of receptor editing. In I
B
+/lacZ reporter mice expressing either innocuous or self-specific knocked in BCRs, β-gal was preferentially expressed in pre–B cells from the mice with self-specific BCRs. Retroviral-mediated expression of a cDNA encoding an I
B
superrepressor in primary bone marrow cultures resulted in diminished germline
and rearranged
transcripts but similar levels of RAG expression as compared with controls. We found that IRF4 transcripts were up-regulated in β-gal+ pre–B cells. Because IRF4 is a target of NF-
B and is required for receptor editing, we suggest that NF-
B could be acting through IRF4 to regulate receptor editing.
Abbreviations used: β-gal, β-galactosidase; BCR, B cell receptor; cDNA, complementary DNA; FDG, fluorescein di-β-D-galactopyranoside; HPRT, hypoxanthine-guanine phosphoribosyl transferase; IgHC, Ig heavy chain; IgLC, Ig light chain; LM-PCR, ligation-mediated PCR; mRNA, messenger RNA; RPS3, ribosomal protein S3; RSS, recombination signal sequence.
© 2009 Cadera et al.
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