A novel Pax5-binding regulatory element in the Ig kappa-locus

作者：Levin Klein Rena; Kirillov Andrei; Rosenbluh Chaggai; Cedar Howard; Bergman Yehudit^*

来源：Frontiers in Immunology, 2014, 5: 240.

DOI：10.3389/fimmu.2014.00240

• V(D)J rearrangement
• DNA methylation
• B cell development
• Pax5
• somatic hypermutation

The Ig kappa locus undergoes a variety of different molecular processes during B cell development, including V(D)J rearrangement and somatic hypermutations (SHM), which are influenced by cis regulatory regions (RRs) within the locus. The Igk locus includes three characterized RRs termed the intronic (iE kappa), 3'Ek, and Ed enhancers. We had previously noted that a region of DNA upstream of the iE kappa and matrix attachment region (MAR) was necessary for demethylation of the locus in cell culture. In this study, we further characterized this region, which we have termed Dm, for demethylation element. Pre-rearranged Igk transgenes containing a deletion of the entire Dm region, or of a Pax5-binding site within the region, fail to undergo efficient CpG demethylation in mature B cells in vivo. Furthermore, we generated mice with a deletion of the full Dm region at the endogenous Igk locus. The most prominent phenotype of these mice is reduced SHM in germinal center B cells in Peyer's patches. In conclusion, we propose the Dm element as a novel Pax5-binding cis regulatory element, which works in concert with the known enhancers, and plays a role in Igk demethylation and SHM.

• 出版日期2014-5-23
• 单位河北医科大学