L10_Development of B-Cells and Generation of Diversity Flashcards
What are the first two constant regions coded after the Variable region?
M and D which are always transcribed together.
What is the enzyme that creates the N-nucleotides? What is unique about it?
TdT (Terminal deoxynucleotidyl transferase). It doesn’t read off a template it just randomly adds to free DNA ends.
What light chain gene is attempted to rearranged first?
Kappa then Lambda.
What is the only case of RNA splicing that is involved in antibody developement?
M and D heavy chains are always transcribed together and variable RNA splicing determines which heavy chain is translated. The splicing also determines if the antibody will be membrane bound or secreted from the cell.
Is Class switching a random process?
No
What is the order of heavy chain genes?
M,D, G3, G1, A1, G2, G4, E, A2
When does somatic hypermutation take place and where?
During class switching in the variable regions.
What enzyme facilitates class switching and hypermutation?
Activation- Induced cytidine Deaminase (AID)
What chains undergo somatic hypermutation?
Light chain and heavy chain
Does the T-Cell receptor undergo Class switching and Somatic hypermutation?
NO, NEVER! it needs to recognize self and non-self and we do not want to screw that up.
What is the result of a RAG deficiency?
The person will have a severe combined immunodeficiency of both B and T cells
What will happen if you lack TdT?
Antibodies that will have lower affinity due to lower variability in you antibodies
What chains in TCR have VDJ and which have only VJ?
alpha and gamma have VJ and beta and delta have VDJ
What enzymes help in joining V, D, and J segments?
Recombinase Activating Genes, RAG proteins (1 and 2)
Is class switching random?
No
