Janet Stavnezer (a) and Chris T. Amemiya (b), (c)
Seminars in Immunology, 2004. 16:257-275
The Evolution of Rearranging Receptor Families
Abstract
This review discusses evolution of the process of Ig heavy chain class switching, relating it to the first appearance of somatic hypermutation (SHM) of variable region genes. First, we discuss recent findings on the mechanism of class switch recombination (CSR) in mice and humans, and then review the mechanisms of expression of Ig heavy chain isotypes from fishes to mammals. Importantly, activation-induced cytidine deaminase (AID), which is essential for CSR and somatic hypermutation, is found in fishes. Although at least some fishes are likely to undergo SHM, CSR is highly unlikely to occur in this group. We discuss the first appearance of CSR in amphibians and how it differs in birds and mammals.
Keywords: Immunoglobulins; Antibody class switch recombination; Somatic hypermutation; AID; IgH gene loci
Corresponding author. Tel.: +1 508 856 4100; fax: +1 508 856 5920.
(a) Department of Molecular Genetics and Microbiology, Program in Immunology and Virology, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA 01655-0122, USA
(b) Molecular Genetics Department, Benaroya Research Institute at Virginia Mason, 1201 Ninth Avenue, Seattle, WA 98101, USA
(c) Department of Biology, University of Washington, Seattle, WA 98195, USA | 
