Genetics of Ig Flashcards
What are the different segments used for Ig synthesis?
Variable (V), Constant (C), Joining (J) and Diversity (D) regions.
Which segment region is only used in heavy chains?
Diversity (D) regions.
Are the gene families (kappa chain, lambda chain and heavy chain) encoded in the same chromosome?
NO
Where is in the light chain CDR1, CDR2 and CRD3 distributed?
CDR1 and CDR2 in the variable region.
CDR3 in the junction between the variable region and the joining region.
How many Constant regions does the Kappa light chain gene have?
One
How many possible variations are for the kappa genes?
175 possible variations
35V genes x 5 J genes = 175 V regions (kappa)
What % of light chains are lambda type?
40%
In what type of mechanism for the light chain formation the J segment is paired with a C segment?
In Lambda light chains
For what do the different Ch encode?
For different isotypes.
Where is in the heavy chain CDR1, CDR2 and CRD3 distributed?
V: CDR1 and CDR2.
V-D-J: CDR3
To what isotype does the first selection correspond?
IgM
What’s the constant region of the first selection in heavy chains?
Mu constant region.
Which enzymes mediate V(D)J recombiantion?
Enzymes involved in DNA repair functions.
RAG1/2, TdT, ligases…
When is the spacer sequence of the recombination signal sequence (RSSs) of 12 bp or of 23 bp?
Heptamer-23bp-Nonamer
Nonamer-12bp-Heptamer
When does the rearrengment process occur?
In lymphocytes during their development.
Irreversible process
