Lecture 15: Immunoglobulin Genes and Generation of Diversity

Non-covalent bonds that link antigen with its receptor

1. Hydrophobic bonds

2. Hydrogen bonds

3. Electrostatic bonds

4. van der Waals bond

Antigen receptor genes

V genes

J genes

C genes

Once the necessary antigen receptor genes are activated, they are transcribed into __ and translated into receptor proteins.

RNA

__ genes code for each receptor chain.

Multiple

Several genes code for __ variable chain.

Each

ONLY __ (or few) genes code for constant chain.

one

Combinatorial association

Process where antigen receptor chains may be paired in different combinations to yield even greater diversity.

Methods of generating immunoglobulin diversity

1. VJ and VDJ gene recombination

2. Base deletion

3. Base insertion

4. Somatic mutation

5. Combinatorial association

6. Gene conversion

7. Receptor editing

Process of gene recombination

Random selection of one gene from each of several groups of genes → Recombining these selected genes → Sequence diversity

No __ gene in light chains!

D

Three gene loci code for immunoglobulin peptide chains:

IGK

IGL

IGH

IGK codes for

kappa light chains

IGL codes for

lambda light chains

IGH codes for

heavy chains

Which mechanism is used for looping out (deleting unwanted genes)

1. Recombinase (RAG1, RAG2)

2. DNA repair enzymes

Mechanisms for generating V-region diversity

1. Base deletion

2. Base insertion

3. Receptor editing

Methods of generating TCR diversity

1. VJ, VJJ, VDJ and VDDJ gene recombination

2. Base deletion

3. Base insertion

4. Combinatorial association