HIs replication Flashcards
what type of virus is HIv
retrovirus
- revers transcirptase- RNA genome into DNA, integration of the proviursu to the host chromsome
- infection for life
- target cell CD4+ cells
- T helper cells
what receptors goes HIV have on its surface and what receptors does it look to bind for on target cells
HIv- GP41 and Gp120 on its surface
Primary receptor- Cd4
secondary receptor- CCR5 or CXCR4
infection need CD4 and one of the secondary receptors
Describe the CC5 receptors and its relatrion to HIv tropism
chemokine recepotr
MAcrophage tropic/ R5 tropic Hiv
R5 tropic HIV strains predominant generlaly in early stage of infection
Drug CC% receptor antagionist- Maravirox
Describe the CXCR4 receptor and its relation to HIV tropoims
chemokine receptor, ligand
T cell tropic HIV (t-tropic/Tropic HIV)
found in later infection
associated with faster T cell clearance
Describe HIv entry into the cell
fusion of viral and cellular memebrane
role of Gp120/Gp41 complex on HIv surface m,embrane
interacts with CD4, this interaction is enhanced the the presence of a chemokine receptor- Confirmation change in GP120
Exposure of GP41- fusion domain ecposure- interacts with emembrane of host cell
membranes fuse
internal components of virus mix with cell- nucleocapsid digested
viral genome and viral enzymes now in the cell
Name a drug which targets HIV entry into the cell
Fusion inhbuitor - enfuviritde (fuson)
describe the action of Reverse transcriptase
reverese transcription
ssRNA—> dsDNA
what drugs are sued agaisnt Reverse trnacriptase?
Nuceloside Reverse Transcriptase Inhbitors (NRTi)
Non-nucleoside reverse transcriptase inhbitor (dont. block the active site, bind to non activeside to cause confirmational change in Rt)
used in combination
Describe the action of HIV enzyme integrase? where on chromsome can it add in the proviral DNA
insertion of protein into chromsome- integrase
anchored on the ends of viral DNA
bring humana dn virzl DNA into position
non-homolgous recombination
must happen in euchromatin
once integrase has inserted the virlsa DNa into the human genome what happens?
viral DNA is trancribed by RNa polymerase into mRNA, infected cells own machinery then used to transcribe the mrAN into new viral proteins in ribsosomes of RER
proteins then shuttled by RER to cell surface, becoem embeeded
get cluster of viral envelope proteins on cell surface
Describe the process of HIV viral maturation
Cleaveg and internal reoriagnisation
assemnbly of proteins and RNa genome at plasma memebrane
budding off new birion
final cleave of Internal polyprotein chain to mature infectious forms inside the virion to becoem infection
internal reorgnasiation- only infectious virion after cleavage and internal re-organisation to give infective organisation
