L05: Organization and Expression of Ig Genes Flashcards
Which chain does this code for?
lambda light chain
Which chain does this code for?
Kappa light chain
Which chain does this code for?
Heavy chain
How are the light chains rearranged?
- A single V is joined to a single J
- This activates the promoter of at the leader region of the V attached to the J
- transcription goes until it reaches stop codon at the end of the constant domain following the J
After gene rearrangement, how are primary transcripts proccessed?
- introns spliced out
- poly-A tail added when leaving ribosome
- leader region joine with RER, poly-A tail removed
- Leader region removed in RER
- Is now a mature ligth chain (peptide)
How does message processing for the Kappa LC differ from that of the Lambda LC?
-extra Js are also removed along with introns
Which gene(s) has/have more than one constant region?
Lambda and heavy chain genes
D regions are only found in the…
Heavy chain gene
How is the heavy chain gene rearranged?
- first a D is joined to a J
- Then a V is joined to that D that joined to a J
There are transcriptional stop signals at the end of every constant region except for:
the mu (µ)
The end of constant regions on the heavy chain gene have:
membrane spanning regions
*Light chains will not have this*
The order of gene rearrangement
- heavy chain
- light chain
only ____ b-cells will splice out the membrane spanning regions of its constant domain
mature, antigen-activated
you will almost never see a soluble ____ -class antibody
D-class
one-turn sequences have ____ bases
12
two-turn sequences have___ turns
23
Which parts of the RSS are cut out when the loops are formed?
- one/two turn sequences
- AT rich region
- parts of the heptamer
After hair-pin loops are cut in the light chains, ___ occurs
P-nucleotide addition
After hair-pin loops are cut in the light chains, ___ occurs
N-nucleotide addition
The first two loops of the CDR are determined by the ___
V region
somatic hypermutation occurs in the ___
lymph nodes
Class switching involves the ____ region of the antibody
the Fc stem region, CDR will remain the same
What motivates class switching?
- TH cells give cytokine signals to the B-cells that say we need a specific (non mu) class of stem
