Retroviruses Flashcards
Do retroviruses have an envelope? What type of genome do they have?
Yes and plus stranded single stranded RNA
What does the core of a retrovirus consist of?
Gag (group-specific antigen), reverse transcriptase, integrase, two identical copies of the viral genomic RNA, and associated tRNA
What two structural additions does retroviral genomic RNA have that makes it similar to eukaryotic mRNA?
A 5 prime cap and a poly A tail
What four proteins do retroviral gag genes usually encode for?
Matrix (MA), Capsid (CA), Nucleocapsid (NC), and Protease (PR)
What is the technical term that describes a reverse transcriptase?
RNA-dependent DNA polymerase
In HIV-1 are viral polymerase and integrase separate proteins or are they translated together and then cleaved?
Translated together then cleaved apart
What proteins do retroviral env genes encode for?
Surface protein (SU) and Transmembrane protein (TM)
What retroviral protein mediates cell attachment?
The SU (surface) protein
What host cell receptor does HIV-1 bind to?
The CD4 receptor
The six regulatory genes of HIV-1 and what each does
Tat (transcriptional transactivator), Rev (rescues unspliced viral RNA), Vpr (G2 arrest), Nef (stimulates viral production), Vpu (stimulates viral release), Vif (prevents hypermutation)
In addition to CD4, what receptors are important for HIV-1 cell entry?
Chemokine receptors (eg CXCR-4 and CCR5)
At what level of CD4+ lymphocytes does AIDS occur?
Below 200 cells per cubic millimeter of blood
Does vertical transmission of HIV occur prenatally, perinatally or post-natally
It can be transmitted in any of these three manners (note that post-natal here implied transmission through breast milk)
Long-term non-progressors
Individuals infected with HIV-1 who do not develop symptoms (1 to 2 percent of pts)
What is HAART and what are its components?
Highly Active Anti-Retroviral Therapy. 2 reverse transcriptase inhibitors and one protease inhibitor
