Chapter 7 Flashcards
Which of the following BEST encapsulates the findings of the Hozumi and Tonegawa experiments?
Light chains are produced by means of somatic rearrangement of germ-line DNA in B cells.
Which of the following gene segments is NOT found in the mouse IgL loci?
D
At which point in the variable segments does the RAG-1/2 complex introduce a single-strand break into the DNA during somatic rearrangement?
Between the coding region and the conserved heptamer
What introduces a transient hairpin that links the two strands in the V(D)J coding regions?
RAG-1/2
What binds cut DNA and retains it in protein-DNA complex?
Ku 70 and Ku 80
What cleaves interstrand hairpin in V(D)J coding regions?
Artemis
What introduces single-strand break between V(D)J coding sequence and heptamer RSS?
RAG-1/2
What introduces nucleotides in a template-independent manner to free 3′ OH created upon cleavage of the interstrand hairpin?
TdT
What closes the final nicks in the sugar-phosphate backbone to generate coding and signal joints?
XRCC4 with DNA ligase IV
What recognizes nonamer RSS to begin lymphocyte receptor rearrangement?
RAG-1/2
Which of the following is NOT a means of generating diversity in the variable regions of the T cell receptor genes?
Somatic hypermutation following activation
How many Dβ-Jβ rearrangements are possible in a normal human thymocyte?
4
The indicated items are found in an IgL gene. Which of the labeled elements serves as a spacer?
12 bp
Where does RAG-1/2 cut the dsDNA depicted in the figure?
Between VL and the 7 bp regions
In which cells are the IgL loci rearranged by RAG-1/2?
Developing B cells
What length must the RSS spacer be to link the above V element to its appropriate D element?
None of the above
To which fundamental process is rearrangement of the above locus tightly linked?
Transcription
Which of the following is capable of undergoing successive rearrangements to prevent the formation of autoreactive lymphocyte receptors?
Both A and B
Which of the following IgH chains is NOT produced as a result of CSR?
δ
Which of the following TCR gene variable regions possesses a “D” segment?
Both A and C
Which of the following accounts for allelic exclusion in rearrangement within the IgH locus?
Rearrangement only occurs on one homolog at a time, and once one homolog has successfully rearranged, the other is methylated to produce heterochromatin.
Which of the following is used to generate diversity in the antibody repertoire?
All of the above
Which of the following components that are essential for rearrangement of the IgH and IgL loci are not utilized in rearrangement of the TCR loci?
All of the above are essential for rearrangement of the TCR loci
Which of the following accounts for the transition from membrane-bound IgM to secreted IgM upon activation of a B cell?
Alternative splicing of pre-mRNA
Deficiency in RAG-1 and/or RAG-2 can affect the proper development of which of the following cell types, resulting in decreased numbers of circulating cells of those types?
Both A and B
