Middleton- Retrovirus, AIDS, and tumor viruses Flashcards
what groups were in the “4H” club risk for contracting AIDS? when was this theory popular
Homosexual men, heroine addicts, Haitians, and hemophiliacs
1970s-1980s
HIV appears to have evolved (genetic evidence) from _____ virus in Africa
simian
Retroviruses have a unique ________ cycle
replication
T/F: Spumaviruses do not causehuman disease
true
Spurmaviruses form “____” structures inside the cell
foamy
Retroviridae: two subfamilies. name them
Orthoretroviridae
Spumaviridae
the Genome of retroviruses is ___ssRNA
(+)ssRNA
the virion of the retrovirus is
enveloped
the _______ ______ are now used to classify retroviruses as simple or complex
Genome contents
______ retroviruses only encode the Gag, Pro, Pol, and Env genes
simple
what is the function of Reverse transcription in Retrovirus replication
it turnes ssRNA genome into dsDNA (allows it to incorporate into the host DNA)
what is meant by “Integration” of a retrovirus?
Virus dsDNA inserts into host DNA making provirus
the transcription of a retrovirus occurs from a _____
provirus
Maturation of retroviruses involves ______ activity
protease
what is the “Defining feature of retroviruses”
reverse transcription
when is reverse transcription initiated?
once nucleocapsid is in cytoplasm
Low _____ levels prevent reverse transcription
NTP
retrovirus infections cannot progress if __________ does not occur
reverse transcription
Reverse transcription is promiscuous between what?
Genome copies
when does the retrovirus ssRNA integrate into the host genome?
during mitosis
the retrovirus dsDNA will Attack target DNA, creating a nick. What joins this DNA back together?
the host cell
T/F: cells infected with a retrovirus can be returned to their previous state with proper antivirals.
False- the integration of virus DNA is permanent
Integration may disrupt host genes causing disease such as what?
cancer
what are the Integration identified oncogenes
1) Transcription factors
2) Secreted growth factors
3) Growth factor receptors
4) Cell signal transduction pathways
T/F: Many defective retroviruses are made during replication
true
Defective viruses are missing at least one of:
gag, pol, or env
defective viruses can carry host genes, which are ________ when they carry oncogenes
tumorigenic
T/F: Many retrovirus infections are benign
true
name the 3 types of disease-causing retroviruses
1) Slow retroviruses
2) Cytopathic retroviruses
3) Acute transforming viruses
leukemia viruses are examples of ____ retroviruses
slow
which type of retrovirus can damage the tissue directly
Cytopathic retroviruses
Acute transforming viruses carry what?
Carry host genes
HTLV stands for what?
Human T-Cell Leukemia Virus
HTLV is what type of virus?
Deltaretrovirus
a species of orthoretrovirinae
T/F: HTLV-1 is a fairly rare viral disease
false- millions of people worldwide are infected
HTLV-1 is transmitted person-to-person, meaning that what activities promote its exchange?
Sharing needles for drug users
Blood transfusions
Sexual transmission
breast feeding
what disease is caused by HTLV-1? what does it infect?
Adult T-Cell Lymphoma/Leukemia (ATLL)
infects memory T-cells
Cells infected with HTLV-1 become transformed, generating _____
tumors
______ is Associated Myelopathy / Tropical Spastic Paraparesis (HAM/TSP). these diseases are caused by what?
HTLV-1
HAM/TSP caused by transfusion of infected blood
HAM/TSP Symptoms and latency period
latency period- 1-3 years after infection
symptoms:
- loss of bladder control
- leg weakness or stiffness in hips/knees
- erectile dysfunction (mainly in men…..)
what are the prevention techniques for HTLV-1?
Eliminate breastfeeding for HTLV-1 positive mothers
Increased screening for blood products
HIV is what type of virus?
Lentivirus
what populations are at greater risk for contracting HIV?
Homosexuals, injection drug users, hemophiliacs, transfusion recipients
where is HIV most prevalent?
sub-saharan africa
Latent period for AIDS –
6 mths to 25 yrs
HIV targets what type of cells?
T-cells (CD4+)
once the Chronic infection is established, what occurs?
Ongoing virus replication & T-cell depletion
once infected with HIV, the risk of _______ infections increases
opportunistic
T/F: antivirals are the only current treatment for HIV infection
true
the HIV virus has a _____ (+)ssRNA genome
Diploid
T/F: the HIV virus only causes AIDS
false- it is a significant cause of certain types of cancer
Acute transforming viruses induce what?
rapid tumor formation
