HIV Replication Cycle (Early Phase)
HIV Life Cycle:
Early Phase
1. Attachment & entry
2. Reverse transcription & synthesis of DNA
3. DNA integration into host genome
Late Phase
1. RNA transcription
2. HIV polypeptides
3. Virion assembly & exit
3. DNA Integration into Host Genome
The excised 3’ nucleotides create a 5’ overhang on each side
* Additionally integrase nicks the host genome at a random position, generating staggered
2-bp ends
HIV ‘DNA’ inserts into the nicked sites in the host genome by ligation
Viral 5’ ends are removed and the gaps are repaired by host repair mechanisms
The overall process generates integrated viral genome called a provirus
Provirus includes 2 copies of the U3-R-U5 region termed the long terminal repeat (LTR)
1. Integrase clips 2 nucleotides off both 3’ ends of viral cDNA = the
excised 3’ nucleotides create a 5’ overhang on each side.
o integrase nicks the host genome at a random position,
generating staggered 2-bp ends
2. HIV ‘DNA’ inserts into the nicked sites in the host genome by ligation.
3. Viral 5’ ends are removed and the gaps are repaired by host repair
mechanisms.
=Generates an integrated viral genome = provirus
Provirus includes 2 copies of the U3-R-U5 region = long terminal repeat (LTR).
When cells are not replicating, HIV can remain in nucleus in non-integrated cDNA form.
Integrase action only occurs in replicating cells (to enable integration of viral cDNA)
HIV Life Cycle:
Early Phase
1. Attachment & entry
2. Reverse transcription & synthesis of DNA
3. DNA integration into host genome
Late Phase
1. RNA transcription
2. HIV polypeptides
3. Virion assembly & exit
3. DNA Integration into Host Genome
The excised 3’ nucleotides create a 5’ overhang on each side
* Additionally integrase nicks the host genome at a random position, generating staggered
2-bp ends
HIV ‘DNA’ inserts into the nicked sites in the host genome by ligation
Viral 5’ ends are removed and the gaps are repaired by host repair mechanisms
The overall process generates integrated viral genome called a provirus
Provirus includes 2 copies of the U3-R-U5 region termed the long terminal repeat (LTR)
1. Integrase clips 2 nucleotides off both 3’ ends of viral cDNA = the
excised 3’ nucleotides create a 5’ overhang on each side.
o integrase nicks the host genome at a random position,
generating staggered 2-bp ends
2. HIV ‘DNA’ inserts into the nicked sites in the host genome by ligation.
3. Viral 5’ ends are removed and the gaps are repaired by host repair
mechanisms.
=Generates an integrated viral genome = provirus
Provirus includes 2 copies of the U3-R-U5 region = long terminal repeat (LTR).
When cells are not replicating, HIV can remain in nucleus in non-integrated cDNA form.
Integrase action only occurs in replicating cells (to enable integration of viral cDNA)
