Exam 4 Flashcards
(132 cards)
1
Q
Ellerman and Bang
A
in 1908, demonstrated that “filterable agents” can produce tumors in chickens
2
Q
Rous
A
discovered that bacteria free filterable agents can cause sarcomas in chickens - Rous Sarcoma Virus
3
Q
Bishop and Varmus
A
discovered the src gene of RSV is found in normal chicken DNA as a proto-oncogene
4
Q
% of human cancers caused by viruses
A
20%
5
Q
number of known human cancer causing viruses
A
6
6
Q
name the 6 human cancer causing viruses
A
- Hepatitis Virus B
- Hepatitis Virus C
- Human Papilloma Virus (HPV)
- Epstein Barr Virus
- Human Herpes Virus 8
- Human T-lymphotrophic virus
7
Q
Human papilloma virus can cause
A
cervical cancer
8
Q
EBV can cause
A
Burkitt’s Lymphoma
9
Q
Human T-lymphotrophic Virus can cause
A
T cell lymphoma
10
Q
5 steps to determine progression of cancer
A
- Apoptosis override
- Autonomy - don’t require exogenous growth signals
- immune escape
- Angiogenesis
- metastasis
11
Q
of retroviruses experimentally shown to induce cancer
A
2
12
Q
retroviruses experimentally shown to induce cancer
A
- Rous Sarcoma Virus
2. Mouse Mammary Virus
13
Q
3 ways retroviruses can cause cancer
A
- may carry a viral oncogene
- may in-activate a tumor suppressor gene
- may activate a cellular proto-oncogene
14
Q
endogenous retroviruses
A
provirus virus integrated into genomic DNA
15
Q
Shope
A
identified 1st DNA tumor viruses
16
Q
Rabbit papilloma virus may have caused the - myth
A
jackalope
17
Q
4 DNA tumor viruses
A
- papilloma virus
- EBV
- Kaposi’s Sarcoma
- HBV
18
Q
EBV can cause tumors in — populations, such as –
A
immune suppressed, those with malaria or HIV-AIDS
19
Q
process of EBV cancer induction
A
v-onc EBNA-2 inserts into c-myc, disrupting cell cycle reg and apoptosis, disruption leads to uncontrolled cell growth
20
Q
Kaposi’s sarcoma is a –
A
HHV-8 virus
21
Q
Karposi’s sarcoma is aggressive in —
A
people with immune supression such as HIV AIDs
22
Q
EBV v-onc
A
EBNA-2
23
Q
EBNA-2 is a —- that
A
v-onc in EBV that integrates into c-myc gene
24
Q
HPV structure
A
small, non-enveloped, icosahedral
25
HPV genome
closed circular dsDNA
26
HPV genome replication takes place in the
nucleus
27
what HPV processes occur in the nucleus
replication, nucleocapsid formation, maturation
28
leading cause of cervical cancer?
HPV
29
malignant cervical cancer tumors contain
integrated HPV-16 DNA
30
number of HPV types
100
31
HPV risk types
low, intermediate, high
32
expression of HPV integrated gene products -- leads to ---
E6 and E7, lead to inactivation of tumor suppressors p53 and Rb
33
tumor suppressor genes inactivated by HPV integration
p53 and Rb
34
HPV E6 leads to
p53 degradation
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HPV E7 leads to
cell cycle activation and proliferation
36
viruses that induce cancer in animals other than humans
adenoviruses and polyomaviruses
37
adenovirus that can induce tumors in hamsters
12
38
2 adenovirus v-oncs
E1A and E1B
39
SV-40 may have a role in -- by --
animal cancer, by binding and inactivating p53
40
SV-40 structure
small non-enveloped icosahedral
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SV-40 genome
cc dsDNA
42
SV-40 -- may bind and inactivate p53
large and small T antigen
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TSEs stands for
Transmissible Spongiform Encephalopathies
44
prions are exremely resistant to (4)
1. strong bases
2. high heat
3. high pressure
4. bleech
45
viroids are
plant pathogens
46
viriods are composed of
RNA
47
Griffith
1st hypothesized TSEs
48
Prion gene
PrP
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2 PrP forms
PrP^c (normal) and PrP^Sc or res (infectious form)
50
Prusiner
isolated PrP
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prion CFR
100%
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1st clinically described TSE
Kuru
53
Kuru is found among
South Fore people of Papua New Guinea
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Kuru passed by ritual of
endo-cannibalism
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Kuru stages
1. Ambulent stage
2. Sedentary stage
3. Terminal stage
56
Kuru ambulent stage
tremors, imbalance, slurred speach, loss of coordination
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Kuru sedentary stage
no longer walk, uncontrolled movement, waves of emotion
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Kuru terminal stage
incontinence, difficulty swallowing, ulceration
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PrP is encoded by the -- gene
PRNP
60
PRNP is gene is on c'some -
20
61
changes to --- of PrP may cause pathogenicity
Beta sheet domain
62
normal PrP is found in -- tissue and -- is prediceted to be important in --
neurological, copper metabolism
63
PrP^res is ---
resistant to degradation by lysosomes
64
3 possible origins of TSEs
infection
inheritance
sporadic formation
65
most common human TSE
Creutzfeldt-Jakob Disease
66
mode of CJD transmission
sporadic or inherited or diet
67
% of CJD that is sporadic
80%
68
inherited forms of CJD (3)
1. CJD
2. Gertsmann-Straussler-Scheinker syndrom
3. Fatal Familial Insomnia
69
varient CJD is aquired via
diet
70
CJD neuroinvasion occurs through the ---
vagus nerve to the brainstem
71
varient CJD early symtomology
memory loss
| emotional instability
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late varient CJD symptomology
neuromuscular degeneration
| persistent vegetative state
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following CJD onset, death occurs -
within one year
74
PrP causes spongiosis of brain tissue, due to -- and -- damaging tissue
PrPres plaques and astrocytosis
75
how did scrapie from sheep get to cows
scrapie infected offal fed to cows
76
BSE was 1st observed
England, 1980s
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human cases of vCJD in england from BSE peaked in
1994
78
BSE mitigated by
surveilance and feed bans
79
chronic wasting disease 1st observed in
northern CO mule deer in the 1960s
80
CWD transmitted by
direct and indirect contact in feces and suliva
81
% white tail deer seropositive for CWD
25%
82
CWD to humans?
no reported cases
83
viroid genome
+sense cc ssRNA
84
viroid structure
rod like, 30nm
85
do viroids code for protein?
no
86
of viroid species
over 40
87
Diener
discovered viroids in potatos
88
viroid 1st discovered in potatoes
potato spindle tuber viroid disease
89
2 viroid families
avsunviroidae and pospiviroidae
90
pospiviroidae structure
rod like
91
number of viroid structural/functional domains
5
92
viroid domain that determines replication
C
93
viroid domain that determines plant pathology
P
94
how do viroids propogate cell to cell
plasmodesmata
95
how to viriods synthesize genome?
host RNA pol
96
method of viroid rep
host RNA pol, rolling circle
97
what processes viroid RNA
viroid hammerhead ribozymes - catalyze cleavage and ligation, then circularized by host ligase
98
bacteriophages infect
bacteria and archaea
99
phages are the --
most abundant "form of life on earth"
100
number of phage particles estimate
10^31
101
first observed phages
Twort
102
discovered phages, used them in phage therapy
d'Herelle
103
phage morphology
binary - have a head and tail
104
most phages have -- genomes
dsDNA
105
MS2 structure
25nm diameter, no tail, 4 genes
106
T4 structure
has head and tail, head composed of 20 proteins
| 200nm, 200 genes
107
2 phage life cycles
lytic and lysogenic
108
most infectous phage stage
lytic
109
in lytic phage stage
phage replicated genome, makes new phage particles, releases from host
110
in lysogenic phage stage
genetic material integrates into the host genome, forming a prophage
111
what is a host called after lysogenic integration
lysogen
112
gene expression in phages
sequential, early, middle and late genes
113
T4 early stage
host like promoters on gene, recognized by RNAP II
114
T4 middle stage
promoters differ from host, expression requires early gene products that help RNAP II bind to pomoter
115
T4 early gene products that aid in promoter binding
AsiA and MotA
116
T4 late stage promoters
defective, require T4 encoded sigma factor for RNAP III recognition
117
another way for phage to control gene expression
encode own RNA pol
118
T7 encodes
its own RNA pol
119
main way for phages to escape host
lysis
120
to escape cell via lysis, phage must
destroy the peptidoglycan cell wall, using phage encoded endolysin
121
what happens upon prophage reactivation?
re-enters the lytic cycle - can happen in response to stress, damage, nutrient limitations
122
phage integration
site specific, done by homologous recombination at DNA sites on phage (attP) and bacteria (attB)
123
phage excision
done by phage encoded excisionase (Xis)
124
phage integration done by
phage encoded Integrase (Int)
125
phage integration occurs by
homologous recombination
126
lysogenic conversion is when
a phage alters the phenotype of a lysogen
127
Shiga toxin is made by
some e coli and shigella
128
Shiga toxin is an example of
lysogenic conversion
129
shiga toxin is encoded on
STX
130
STX expression occurs
during STX replication in response to stress
131
shiga toxin is release when the host
lyses
132
big issue about shiga toxin
STX carrying phage can infect normal e coli of gut, convert them to carryers, cause dysentery or hemolytic uremic syndrome
