A striking example of convergent evolution observed for the ggFcR:IgY interaction closely resembling that of mammalian FcR:IgG

作者：Schreiner Barbara; Viertlboeck Birgit C; Goebel Thomas W

来源：Developmental and Comparative Immunology, 2012, 36(3): 566-571.

DOI：10.1016/j.dci.2011.09.013

• Chicken
• Fc receptor
• Evolution
• IgY

We have recently identified a novel IgY specific chicken FcR (ggFcR) on chromosome 20, a region where no FcR gene is present in mammals. Serially deleted IgY fusion proteins were tested in a reporter assay to identify C-H domains involved in ggFcR binding. Single C-H domains did not bind to ggFcR, whereas Fc upsilon 2 to Fc upsilon 4 induced good and the Fc upsilon 3 to Fc upsilon 4 domains moderate activity. When IgY from diverse birds were assayed, only IgY from gallinaceous birds showed binding, which enabled us to pinpoint several potential contact sites by a sequence comparison and molecular modelling. Point mutations of critical residues at these sites revealed the Fc upsilon 2 and Fc upsilon 3 domains as major ggFcR:IgY binding sites similar to mammalian IgG. These results demonstrate that ggFcR has a contact site to IgY which closely resembles that of human IgG bound to FcR.

• 出版日期2012-3