Test 2: retro Flashcards
baltimore classification
positive sense RNA into negative sense DNA then added into host DNA
retrovirus are
enveloped, diploid linear positive sense ssRNA
retrovirus bring — into the cell with them
reverse transcriptase (RNA-dependent DNA polymerase
integrase- helps put viral DNA into host chromosome
protease- cleaves
tRNA- primer for reverse transcription reaction
— which mediates insertion of viral DNA into host
chromosome
Integrase
retorovirus
— which cleaves specific sites within Gag and Gag-
Pol precursor protein
Protease
retrovirus
retrovirus has what three genes
gag
pol
env
— are found at the beginning and the end of the retrovirus gene
LTR- long terminal repeats
acts an enhancer and promoter- can accidently cause cancer by triggering the wrong gene
Gag protein creates
structural
matrix, capsid, nucleocapsid
retrovirus
Pol protein encodes for —
protease
reverse transcriptase (DNA polymerase and RNase H activity)
integrase
retrovirus
Env protein encodes for
surface glycoprotein
transmembrane protein
accessory genes in retroviruses help
promote viral expression
avoid host immune system
retrovirus binds to host cell by —
surface envelope proteins
retrovirus gets into host cell by
virus host cell membrane fusion
diploid ssRNA retrovirus becomes — inside the host cell
reserve transcriptase into dsDNA that will move into nucleus and integrase enzyme will insert dsDNA randomly into host genome
provirus
what is a retrovirus provirus?
diploid ssRNA will reverse transcriptase into dsDNA and be randomly added into the host genome with the help of integrase enzyme
transcription of retrovirus is by
host RNA polymerase II
retro first reverse transcriptase into dsDNA, integrase adds it to host DNA, then RNA polymerase comes in and makes viral mRNA
LTR at the beginning and end of the viral genome will help trigger the RNA polymerase to start its job
how does retrovirus get out of the cell
virion budding
host cell does not die!
protease helps retrovirus —
translation and viron assembly
surface encelope protein for retrovirus is —
host/species specific
because retrovirus are — they can be killed by disinfectants
enveloped
why are animals considered persistently infected for retoviruses
viral genome added into host genome- even if not shedding can not get rid of the provirus retroviral dsDNA
— in retrovirus has no proof reading and leads to high mutation
reverse transcriptase
takes diploid viral ssRNA into dsDNA
mutations make it hard for host to see virus
genetic transmission of retrovirus leads to
endogenous retovirus
part of the genome- passed to baby
3 ways retroviruses can cause cancer
insertional mutagenesis
capture and expression of host proto-oncogene
direct coding of oncogenic proteins
insertional mutagenesis of retrovirus cause cancer by
trigger the over expression of host proto-oncogenes leading to uncontrolled cell growth
LTR can effect genes that are close - cis- activation
tat can effect gene that are far away- trans-activation
cis-activation of cellular oncogenes by retrovirus
LTR will trigger transcription of host proto-oncogene that is close by
trans-activation of cellular oncogenes by retrovirus
accessory gene TAT is free floating transcriptional activator, will float around and activate host genes
c-onc
(cellular oncogene, aka proto-oncogene), a normal gene
that is involved in cell growth and division of host cell
v-onc
(viral oncogene), a cellular oncogene incorporated in the
viral genome
normal host gene is put into the viral genome- now has no controlling factors and will replicate with the virus
many V-onc containing ciruses are — and require a replication competent — to provide missing viral proteins
replication defective (it is broken)
helper virus (helps restart the virus)
— is replication incompetent and needs co infection with feline leukemia virus to replicate
Feline sarcoma virus
Feline leukemia virus host are —
domestic and wild cats
— is the loving virus and is spread by mutual grooming and fleas
Feline leukemia virus
retrovirus
transmission of FeLV is by
mutual grooming and fleas
loving virus
retrovirus
what version of FeLV cause anemia and immunosuppression
exogenous
FeLV-A
can mutate with endogenous FeLV to form FeLV-B that causes lymphoma
FeLV-B
oncogenic- cause lymphoma in cats
caused by exogenous virus (FeLV-A- anemia and immunosuppression) mutates with endogenous virus and creates FeLV-B
retrovirus
Feline sarcoma virus
host needs to be infected with FeLV for feline sarcoma virus to replicate (oncogene capture)
recombination of FeLB with host cell genome containing oncogenes
needs envelope glycoprotein from FeLV
old cats- solitary tumors
young cats- multifocal tumors
retrovirus
—- is the fighting virus
Feline immunodeficiency virus (FIV)
transmission in saliva, blood, transplacental
cause infection of lymphocytes, monocytes and loss of CD4 T cells
how is FIV trasmitted
in saliva, blood; Biting: Virus is present in saliva,
fighting males, queen to kittens. Vertical: transplacental
Fight disease
retorvirus
symptoms of FIV
chronic gingivitis, infection of lymphocytes, decreases T cell, lymphadenopathy, leukopenia
feline immunodeficiency virus
retrovirus
is a cat is FIV positive on Snap test
possible infection
can be false positive from vaccine
positive FeLV snap test
definite infection
but doesn’t tell A(anemia) or B(cancer)
retrovirus
FIV or FeLV cause cancer
FeLV
FIV- cause immunofeficiency- lentivirus- decreased T cell count
equine infectious anemia virus host are —
horses
donkeys, mules, zebra
equine infectious anemia virus (EIAV) is spread by
blood born- horse flies
retrovirus
Equine infectious anemia virus cause
lentivirus
infectes macrophages and then lymphocytes
fever, anemia, bloodstained feces
80% fatal
acute or chronic relapsing disease
retrovirus
treatement for equine infectious anemia virus
NO treatment
must be isolated for life or culled
disease can be chronic relapsing disease with asymptomatic but persistent infection
retrovirus
treatment for FeLV
vaccine
keep cats seperated- no grooming
test for EIAV
coggins test
antigen- subjective interpretation
equine infectious anemia virus
retrovirus
Caprine arthritis-encephalomyelitis (CAE) is caused by
infected milk
if you remove kids reduce infection rate by 90%
retrovirus in goats
two syndromes caused by CAE
1) encephalomyelitis in kids 2-4 months of age, (paralyzed hind end)
2) arthritis in goats from about 12 months of age onward.
caprine arthritis-encephalomyelitis (CAE)
retrovirus
bovine leukemia virus host are
cattle and water buffalo
deltaretrovirus
transmission of bovine leukemia virus
through bodily fluids- blood and milk
deltaretrovirus
symtoms of bovine leukemia virus
Most cases subclinical, 30%
eventually develop persistent lymphocytosis without clinical signs
* 1-3% Develop multicentric lymphosarcoma by 4-8 years of age
deltaretrovirus
what retrovirus may lead to human breast cancer?
bovine leukemia virus
deltaretrovirus
transmission of avian leukosis virus
horizontally
congenitally
genetically
alpharetrovirus
symptoms of avian leukosis virus
Horizontal transmission often apathogenic, some develop leukemia
or lymphoma.- chronic viremia, tolerance, + leukemia
Congenital infection – high rates of shedding, develop various neoplastic conditions, no viremia, no leukemia
RSV
alpharetrovirus
