Which of the following mechanisms produces the MOST diversity in T cell receptors?
Question
Which of the following mechanisms produces the MOST diversity in T cell receptors?
Solution
The mechanism that produces the most diversity in T cell receptors is the process of V(D)J recombination.
Here are the steps:
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T cell receptors (TCRs) are composed of two different protein chains, either alpha and beta or gamma and delta. Each of these chains is encoded by separate genes.
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Each chain gene is composed of multiple segments: Variable (V), Diversity (D), and Joining (J) segments. The beta and delta chains also have a Constant (C) segment.
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During T cell development in the thymus, these segments are randomly rearranged in a process called V(D)J recombination. This process is mediated by enzymes called RAG1 and RAG2.
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The V, D, and J segments are cut and rejoined in different combinations, creating a unique sequence at the junctions. This is known as junctional diversity.
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The process of V(D)J recombination can result in millions of different TCRs, each capable of recognizing a different antigen. This is the primary mechanism for generating TCR diversity.
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In addition to V(D)J recombination, further diversity is generated by the addition or deletion of nucleotides at the junctions between segments, a process known as N-region addition.
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Finally, each TCR is a heterodimer, meaning it is made up of two different protein chains. The pairing of different alpha and beta or gamma and delta chains can also contribute to TCR diversity.
So, the most diversity in T cell receptors is produced by the combination of V(D)J recombination, junctional diversity, N-region addition, and chain pairing.
Similar Questions
Which of the following are mediated by antigen-specific T-cells and nonspecific cells of the immune system?
The T cell receptor (TCR):Select one alternative:Has enormous binding diversity created by gene segment rearrangement.Consists of 2 protein chains, each with variable and constant domains.Contains only one antigen-binding site.All of the above
T cell maturation and development of their antigen-specific receptors takes place in the . B cells mature in the where they also develop their specificity to a single antigen. This specificity in both B and T cells is made possible through genetic . The genes that code for the variable regions of both B and T cell receptors are cut and spliced during the process of both cells. Because genetic rearrangement occurs at the level of the rather than in the RNA following , the changes are permanent, resulting in each cell being capable of binding to a single antigen in a pool of up to 1018 possible variations. B cell receptors are that are comprised of four and have two identical antigen binding sites. The region of the immunoglobulin is embedded in the cell membrane, and the variable regions are facing outward in order to bind to their potential antigenic match. Unlike B cell receptors, T cell receptors are comprised of two polypeptides and have antigen binding site(s) that is exposed. Like B cell receptors, their specificity to a single antigen is determined any encounters with antigens.
Rearrangement of the T cell receptor _______ gene results in the deletion of the T cell receptor _____ gene.1 pointα; γα; δβ; γβ; δδ; α
What must protein antigens be processed into and bound onto to be recognised by a T-Cell Receptor?
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