Chapter 7

Question 1

Which of the following BEST encapsulates the findings of the Hozumi and Tonegawa experiments?

Answer 1

Light chains are produced by means of somatic rearrangement of germ-line DNA in B cells.

Question 2

Which of the following gene segments is NOT found in the mouse IgL loci?

Answer 2

D

Question 3

At which point in the variable segments does the RAG-1/2 complex introduce a single-strand break into the DNA during somatic rearrangement?

Answer 3

Between the coding region and the conserved heptamer

Question 4

What introduces a transient hairpin that links the two strands in the V(D)J coding regions?

Answer 4

RAG-1/2

Question 5

What binds cut DNA and retains it in protein-DNA complex?

Answer 5

Ku 70 and Ku 80

Question 6

What cleaves interstrand hairpin in V(D)J coding regions?

Answer 6

Artemis

Question 7

What introduces single-strand break between V(D)J coding sequence and heptamer RSS?

Answer 7

RAG-1/2

Question 8

What introduces nucleotides in a template-independent manner to free 3′ OH created upon cleavage of the interstrand hairpin?

Answer 8

TdT

Question 9

What closes the final nicks in the sugar-phosphate backbone to generate coding and signal joints?

Answer 9

XRCC4 with DNA ligase IV

Question 10

What recognizes nonamer RSS to begin lymphocyte receptor rearrangement?

Answer 10

RAG-1/2

Question 11

Which of the following is NOT a means of generating diversity in the variable regions of the T cell receptor genes?

Answer 11

Somatic hypermutation following activation

Question 12

How many Dβ-Jβ rearrangements are possible in a normal human thymocyte?

Answer 12

4

Question 13

The indicated items are found in an IgL gene. Which of the labeled elements serves as a spacer?

Answer 13

12 bp

Question 14

Where does RAG-1/2 cut the dsDNA depicted in the figure?

Answer 14

Between VL and the 7 bp regions

Question 15

In which cells are the IgL loci rearranged by RAG-1/2?

Answer 15

Developing B cells

Question 16

What length must the RSS spacer be to link the above V element to its appropriate D element?

Answer 16

None of the above

Question 17

To which fundamental process is rearrangement of the above locus tightly linked?

Answer 17

Transcription

Question 18

Which of the following is capable of undergoing successive rearrangements to prevent the formation of autoreactive lymphocyte receptors?

Answer 18

Both A and B

Question 19

Which of the following IgH chains is NOT produced as a result of CSR?

Answer 19

δ

Question 20

Which of the following TCR gene variable regions possesses a “D” segment?

Answer 20

Both A and C

Question 21

Which of the following accounts for allelic exclusion in rearrangement within the IgH locus?

Answer 21

Rearrangement only occurs on one homolog at a time, and once one homolog has successfully rearranged, the other is methylated to produce heterochromatin.

Question 22

Which of the following is used to generate diversity in the antibody repertoire?

Answer 22

All of the above

Question 23

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?

Answer 23

All of the above are essential for rearrangement of the TCR loci

Question 24

Which of the following accounts for the transition from membrane-bound IgM to secreted IgM upon activation of a B cell?

Answer 24

Alternative splicing of pre-mRNA

Question 25

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?

Answer 25

Both A and B