Ig Genetics Flashcards
(101 cards)
1
Q
exons for light chain
A
V & J
2
Q
exons for H chain
A
V & D & J
3
Q
when you get germline DNA, myou will encounter
A
gene segments
4
Q
gene segments
A
what encodes L and H chains
5
Q
at dna level a b cells says “i’m no longer going to be like any other cell in the body, i’m going to create my own pacakge”
A
V and J segments, can choose the V and J and rearrange them at DNA level
6
Q
for heavy chain it’s similar with key main difference that V region chooses from
A
3 areas
7
Q
light chain b ell gets to choose from
A
V and J
8
Q
Heavy chain chooses from
A
V, D, J
9
Q
how many different choices for heavy chain do we have
A
9
10
Q
L and H chains are encoded by
A
gene segments
NOT gene
11
Q
how many types of light chains
A
2
12
Q
at DNA level choose region by selection and then can do
A
transcription
13
Q
after transcription
A
RNA splicing
14
Q
after mRNA
A
translation
15
Q
after translation
A
H or L chain protein
16
Q
all of today’s lecture and all these notecards are regarding
A
pre-antigen exposure
17
Q
a number of V choices, so all cells have a bunch of different V gene segments, J gene segments, and heavy chain will also have
A
D gene segments
18
Q
when particular stem cell says they want to be B cell what is firs thing that will happen
A
somatic recombination
19
Q
somatic recombination
A
will help loop out DNA, it is excised as circle - it is gone forever
20
Q
what is excised from somatic recombination is
A
gone forever
21
Q
after somatic recombination you have
A
V1J2 rearranged gene
22
Q
light chains have choice of
A
lambda or kappa
23
Q
heavy chains have choice of
A
V, D, J, C
24
Q
for lambda have a bunch of what choices
A
V segments - around 30
25
lambda and kappa etc are at what level
germline DNA level
26
how many choices for kappa
35 choices for V segments
5 choices for J
one C
27
how many V segment choices for heavy
40
28
how many D segment chocies for heavy chain
23
29
how many J segment choices for heavy chain
6
30
when you make a heavy IgM it will either have what light chain
kappa or lambda, not both
31
when there is chocie for rearrangement for gene segments it is
final
32
VJ rearranged segment of light chain DNA is going to become
V region of protein level of light chain
33
what are going to form variable domain through DNA rearrangment or somatic recombination
VJ or VDJ
34
what in light chain forms at protein level the variable domain
VJ
35
what in heavy chain forms at protein level the variable domain
VDJ
36
go through steps starting with germline DNA to polypeptide chain
pg 13
37
IgM has how many constant regions
4
38
each constant region coded by separate
exon
39
C(L) will be a part of
constant region of light chain
40
when you look at different regions, ex: in light chain decide want to be B cell and need to choose particular V and J, the process of this is mediated by
flanking DNA sequences
41
what are some of the bad things that could happen with the recombinatino to make b cells
cancer
| autoimmune
42
Recombination Signal Sequences
the heptamer and nonamer surrounding
43
the rule for things to go well
spacer in between RSS
44
RSS stands for
recombination signal sequences
45
spacer is always going to be
23 or 12
46
will always combine spacer of what number to another spacer of what number
12 to 23
47
heptamer and nonamer are going to be
what joins the segments together
48
will you ever see spcer with 23 joining another spacer of 23
no
49
RAG protein is only on
in very specific cells - specifically b and t cells
50
RAG does what
mediates the random recombination of gene segments
| it mediates the creation of the loop
51
what creates the loop connecting the V it wants with J it wants
RAG-1/2
52
RAG-1/2 binds
RSS
53
how many potential antibodies just by all the V and D and J choices, how many potential proteins?
1.6 million
54
how many different t cell/bcell can we have
a billion
55
how does cell go from having 1.6 million options to a billion
DNA hairpin forms when two segments are being joined together, and it flips open, generating palindromic nucleotide
b/c it's not perfect now it gives us more combinations.
TdT out of nowhere will make nucleotides - will change the end of p-nucleotides to make n-nucleotides
and we have a billion possibilities
56
what is p nucleotide
palindromic nucleotide
57
Tdt will do what
make new nucleotides
58
TdT stands for
Terminal deoxynucleotidyl Transferase
59
N-nucleotides are added by
TdT
60
P-nucleotides added by
Rag
61
unpaired nucleotides are removed by
exonuclease
62
what will fill in gaps in DNA
DNA polymerase and DNA ligase
63
what are the effects of p-nucleotide and n-nucleotdie addition
Removal or addition of nucleotides at the end of a gene segment can enhance antibody diversity but may also result in premature chain termination.
64
CDR is what
complementary determining region
65
what is other name for CDR
HV (hypervariable region)
66
what determine the antigen specificity of Ig moelcule
hypervariable region
67
CDR3 has
a lot of PN nucleotides - most diverse and most important in binding with the epitope
68
CDR1, CDR2, CDR3 all are involved in
binding of epitope
69
in light chain what are V and J segments connected by
just P nucleotides
70
In heavy chains what are segments connected by
P and N nucleotides
71
antibodies are expressed on cell surface are expressed as membrane anchored
glycoprotein
72
the heavy and light chains are assembled where
ER
73
once you brought together DJ segments you will be
B cell
74
what are the stages for B cell maturation
lymphoid stem cell
Pro-B
Pre-B
75
pre-b you will express
real and final heavy chain
76
what is surrogate light chain
its like a practice light chain
77
what are components of surrogate light chain
VpreB
| lambda5
78
what is allelic exclusion
if you use mom's allele you shut down dad's allele. or same for opposite. b/c you have one chain ready
79
what stage does allelic exclusion happen
pre-BCR
80
Ig beta and alpha are signal chains that contain
ITAM
81
what is difference b/w pre-BCR and IgM
surrogate light chain
82
draw out b cell maturation prior to antigen exposure
pg 31
83
why is immature b cell immature
doesn't have IgD on it yet
84
what is H chain configuration for Pro-BCR
DJ rearranged
85
if antibody is created and it's against self, does the body want it? what happens
no - they are tested and if they are against self they die
86
before you become mature B you are
tested - to see if you are against self
87
VDJ will become
variable region
88
if you are a B cell you will for sure make
IgM IgD
89
there are different exons that code for
IgM and IgD. (as well as IgA, IgE, etc. but IgM and IgD are what are made before antigen exposure)
90
what will happen prior to antigen exposure
will make mu and delta (M and D)
91
what will happen after antigen exposure
will make other parts of the chromosome, gamma, alpha, epsilon
92
making mature IgM and IgD by what process
alternative splicing
93
how many constant regions of IgM chain
4
94
how many exons for delta
four
95
primary transcript has RNA that contains
all exons for M and all exons for D
96
once you have RNA you can do alternative splicing and you choose
if you want to make IgM or IgD, so you would splice out one or the other.
97
DNA of IgM and IgD will remain
the same
98
primary RNA transcript will remain the
same
99
what is another name for mature B cell
naive
100
what are on memory B cells
IgG, IgA, IgE
| "GAE"
101
review summary slide
pg 35
