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7. Organization and rearrangement of the antigen receptor genes: Difference between revisions
7. Organization and rearrangement of the antigen receptor genes (view source)
Revision as of 17:21, 15 January 2023
, 15 January 2023→Organization and recombination of the immunoglobulin genes, VDJ recombination
(Created page with "== Organization and recombination of the immunoglobulin genes, VDJ recombination == For the adaptive immune system to work, each individual B-cell has to create different antibodies that can bind to different antigens, so that when a pathogen invades, at least one antibody can bind to one of the pathogen’s antigens. Because antibodies are just protein transcribed from DNA, the immunoglobulin-coding gene in each B-cell must be slightly different. This is done by recombi...") |
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For the adaptive immune system to work, each individual B-cell has to create different antibodies that can bind to different antigens, so that when a pathogen invades, at least one antibody can bind to one of the pathogen’s antigens. Because antibodies are just protein transcribed from DNA, the immunoglobulin-coding gene in each B-cell must be slightly different. This is done by recombination of the DNA, which deletes certain elements in the gene to make sure one B-cell gets a unique copy. | For the adaptive immune system to work, each individual B-cell has to create different antibodies that can bind to different antigens, so that when a pathogen invades, at least one antibody can bind to one of the pathogen’s antigens. Because antibodies are just protein transcribed from DNA, the immunoglobulin-coding gene in each B-cell must be slightly different. This is done by recombination of the DNA, which deletes certain elements in the gene to make sure one B-cell gets a unique copy. | ||
== VDJ recombination == | |||
Starting with the heavy chain, it’s gene looks like this. Each box is a genetic segment that makes up the gene. The red segments are called “variable” (V), the green are called “diversity” (D), the yellow are called “joining” (J), and the blue are constant and are not modified. | Starting with the heavy chain, it’s gene looks like this. Each box is a genetic segment that makes up the gene. The red segments are called “variable” (V), the green are called “diversity” (D), the yellow are called “joining” (J), and the blue are constant and are not modified. | ||
[[File:Ig heavy chain gene.png|center|thumb|536x536px|The organization of the Ig heavy chain gene. The red are called «variable» segments, the green «diversity», the yellow «joining» and the blue «constant». The segments are very underrepresented. There are actually 65 V segments, 27 D and 6 J.]] | [[File:Ig heavy chain gene.png|center|thumb|536x536px|The organization of the Ig heavy chain gene. The red are called «variable» segments, the green «diversity», the yellow «joining» and the blue «constant». The segments are very underrepresented. There are actually 65 V segments, 27 D and 6 J.]] | ||