What is meant by junctional diversity?
Junctional diversity describes the DNA sequence variations introduced by the improper joining of gene segments during the process of V(D)J recombination.
How does junctional diversity occur?
Junctional diversity results from the imprecise joining of gene segments and from the addition of nucleotides to the DNA sequence at splice sites. TdT adds up to 15 nucleotides to the DNA sequence of human VH and JH regions.
How many VDJ combinations are possible?
Since the nucleotides are chosen at random, any one of the 20 amino acids can be encoded at each site of N nucleotide addition. Thus, on average, 20 × 20 × 20 × 20 = 160,000 possibilities for additional amino acids can arise in a given VDJ joint.
What is meant by antibody diversity?
Our body responds to various pathogens such as bacteria and viruses, producing a wide variety of antibodies that can bind to specific antigens. This is called the “diversity” of an antibody. The diversity of antibodies is created by the combination of variable regions of H chains and L chains.
What is junctional flexibility?
Junctional flexibility: But the joining of coding sequences is often imprecise. Flexible joining in the coding sequences generates several productive combinations that encode alternate amino acids at the coding joint. Consequently, diversity is generated. This phenomenon is referred to as junctional flexibility.
What do you understand by somatic recombination explain?
Somatic recombination, as opposed to the genetic recombination that occurs in meiosis, is an alteration of the DNA of a somatic cell that is inherited by its daughter cells.
How does VDJ recombination create diversity?
V(D)J recombination is the mechanism of somatic recombination that occurs only in developing lymphocytes during the early stages of T and B cell maturation. It results in the highly diverse repertoire of antibodies/immunoglobulins and T cell receptors (TCRs) found in B cells and T cells, respectively.
What is VDJ sequencing?
Here, we describe VDJ sequencing (VDJ-seq), which accurately quantitates immunoglobulin diversity at the DNA level in an unbiased manner. This is accomplished with a single primer-extension step using biotinylated J gene primers.
Why is B cell diversity important?
Given that each B cell can only produce antibody with one specificity, and that there are an enormous variety of organisms that can infect us, the immune system needs to generate vast numbers of B cells that each produce a different antibody.
What does VDJ code for?
– In heavy chains, the V, D and J segments encode the variable domain while the C segment encodes the constant domain. – The heavy chain locus has multiple V (variable) segments, multiple D (diversity) segments, multiple J (joining) segments and multiple C (constant) segments.
How does Vdj recombination work?
VDJ recombination is the process by which T cells and B cells randomly assemble different gene segments – known as variable (V), diversity (D) and joining (J) genes – in order to generate unique receptors (known as antigen receptors) that can collectively recognize many different types of molecule.
What does VDJ recombination stand for?
variability, diversity, and joining
VDJ stands for variability, diversity, and joining, respectively, and VDJ rearrangement has 4 key characteristics that help ensure that each antigen receptor is unique.