Di Nola and Neuberger (2002) reported that activation-induced deamination (AID) of cytosine to uracil leads to hypermutation.
In this figure, you can see that replacing the NH2 with an O leads to the conversion of C -> U in the variable region of the light and heavy chain gene segments. When the B cells try to repair the resulting mismatch, several outcomes are possible:
These base changes lead to altered binding affinities. Those B cells with improved affinity will be clonally selected and they will proliferate.
References
© Copyright 2003 Department of Biology, Davidson College, Davidson,
NC 28035
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