Recombination signal sequences

[1] Recombination signal sequences guide the enzyme complex to the V, D, and J gene segments that will undergo recombination during the formation of the heavy and light-chain variable regions in T-cell receptors and immunoglobulin molecules.

[1] RSSs are located between V, D, and J segments of the germ-line DNA of maturing B and T lymphocytes and are permanently spliced out of the final Ig mRNA product after V(D)J recombination is complete.

[1][4] The RAG1/RAG2 complex then introduces a nick at the 5' end of the RSS heptamers adjacent to the coding regions on both the D and J segments, permanently removing the loop of intervening DNA and creating a double-stranded break that is repaired by VDJ recombinase enzymes.

[3] Some infants born with autosomal recessive SCIDS lack a functional copies of the genes that code for the RAG1/RAG2 enzyme complex because of missense mutations.

[5][6] These infants will produce a non-functional RAG1/RAG2 enzyme complex that cannot recognize RSSs and therefore cannot initiate V(D)J recombination effectively.

The RAG1/RAG2 enzyme complex recognizes the heptamer sequences flanking the V and J coding regions and nicks their 5' end, releasing the intervening DNA between the V and J coding regions.