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Updated: Jun 25, 2026

Analysis of Somatic Hypermutation in the JH4 intron of Germinal Center B cells from Mouse Peyer's Patches
Published on: April 20, 2021
DNA targets of AID evolutionary link between antibody somatic hypermutation and class switch recombination
Jason A Hackney1, Shahram Misaghi, Kate Senger
1Genentech, Immunology Discovery Group, South San Francisco, California 94080, USA.
Abstract:
As part of the adaptive immune response, B cells alter their functional immunoglobulin (Ig) receptor genes through somatic hypermutation (SHM) and/or class switch recombination (CSR) via processes that are initiated by activation induced cytidine deaminase (AID). These genetic modifications are targeted at specific sequences known as Variable (V) and Switch (S) regions. Here, we analyze and review the properties and function of AID target sequences across species and compare them with non-Ig sequences, including known translocation hotspots. We describe properties of the S sequences, and discuss species and isotypic differences among S regions. Common properties of SHM and CSR target sequences suggest that evolution of S regions might involve the duplication and selection of SHM hotspots.
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