Mystery Solved: How Lymphocyte Receptors are Encoded by a Few Genes

For Immunology Chapter 7 Day 1

1. Compare germline and somatic hypermutation theories.
2. Hozumi and Tonegawa tested the idea that Ig light chains were a mosaic of variable and constant domains.  What does this mean?
3. What was Hozumi and Tonegawa’s method for testing this?
   • What cells did they use?  Why?
   • How did their assay work?
   • Can you draw a putative genomic map of this?
4. If domains are ~110 aa in length.  The variable gene segment accounted for 97 aa.  Where were the remaining 13 aa coming from?
5. What is the reason that gene segments are called V, D, and J?  Spend some time discussing the “D” segment name in terms of protein structure