Ingham-2: V(D)J Recombination

Question 1

2 general mechanisms for generating different specificities of Abs and TCRs

Answer 1

combinatorial and junctional diversity

Question 2

Germ-line theory

Answer 2

Ab diversity is generated by recombining separate DNA segments in germ-line of genome of B cells

Question 3

Somatic mutation theory

Answer 3

Ab variable regions undergo mutation in B cells to generate many diff. Ab

Question 4

What segments do light chains have?

Answer 4

V, J

Question 5

What segments do heavy chains have?

Answer 5

V, D, J

Question 6

Combinatorial diversity is?

Answer 6

Combining different V and J or V, D, and J segments to make many different kinds of heavy and light chains

Question 7

What is combinatorial diversity also called?

Answer 7

V(D)J recombination

Question 8

2 factors that contribute to combinatorial diversity

Answer 8

• VDJ and VJ recombination

- combining of heavy and light chains

Question 9

What is RSS?

Answer 9

Recombination Signal Sequence

Question 10

What sequence is conserved in RSS?

Answer 10

heptamer-spacer-nonamer

Question 11

Size of nucleotides spacer?

Answer 11

12 or 23bp

Question 12

What is the 12/23 rule?

Answer 12

RSS with 12bp spacers can only recombine with RSS with 23bp spacers

Question 13

What spacer is in 3’ of V-kappa?

Answer 13

12bp RSS

Question 14

What spacer is in 5’ of J-kappa?

Answer 14

23bp RSS

Question 15

What spacer is in 5’ and 3’ of D segment?

Answer 15

12bp

Question 16

What spacer is in 3’ of VH?

Answer 16

23bp

Question 17

What spacer is in 5’ of JH?

Answer 17

23 bp

Question 18

RAG-1/2 protein function

Answer 18

• catalyze DNA strand breakage

- required for VDJ recombination

Question 19

Function of Artemis?

Answer 19

• nicks hairpin made during recombination at one spot

Question 20

How is junctional diversity made? (light chain)

Answer 20

Nicks made by Artemis are fixed by adding P (Palindromic) nucleotides

Question 21

How is junctional diversity made in heavy chains? (x2)

Answer 21

• exonuclease trimming

- addition of N (non-templated) NTs by

Question 22

What are exonucleases that can perform exonuclease trimming? (x2) (heavy chain)

Answer 22

• Artemis

- Rag proteins

Question 23

What add N NTs on heavy chains?

Answer 23

TdT (terminal deoxynucleotidyl transferase)

Question 24

What is the major target of combinatorial/junctional diversity?

Answer 24

CDR3

Question 25

Does somatic hypermutation happen in T cells?

Answer 25

No