Cellular and Molecular Biology

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Antibody Diversity: Mechanism of Ig Gene DNA Recombination


The variable region of both the heavy and light chain Ig genes undergoes DNA rearrangements to produce functional and unique antibody proteins. Extensive research has revealed some of the details of the mechanism of DNA recombination required to mediate these rearrangements.

One important discovery was the presence of unique recombination signal sequences (RSSs) flanking each of the V, D, and J gene segments in the germ-line DNA.

Which of the following statements about the role of RSSs in Ig gene rearrangement is FALSE?


RSSs contain conserved palindromic sequences that are required for recombination.


RSSs are retained in the DNA sequence of the rearranged Ig gene once recombination is complete.


Recombinase enzymes bind to the RSSs to initiate the DNA recombination reaction.


There are two different types of RSSs present in the DNA: one-turn RSSs and two-turn RSSs.