AIDS InfoNet www.aidsinfonet.org
Fact Sheet Number 106
HIV LIFE CYCLE
A Project of the New Mexico AIDS Education and Training Center. Partially funded by the National Library of Medicine.
Fact Sheets can be downloaded from the Internet at http://www.aidsinfonet.org
1 Free Virus
2 Binding and Fusion: Virus binds to
a CD4 molecule and one of two
“coreceptors” (either CCR5 or CXCR4).
Receptor molecules are common on
the cell surface. Then the virus fuses
with the cell.
3 Infection: Virus
penetrates cell. Contents
emptied into cell.
4 Reverse Transcription: Single
strands of viral RNA are converted
into double-stranded DNA by the
reverse transcriptase enzyme.
5 Integration: Viral DNA
is combined with the cell’s
own DNA by the integrase
6 Transcription: When the
infected cell divides, the viral DNA
is “read” and long chains of
proteins are made.
7 Assembly: Sets of viral protein
chains come together.
pushes out of the
cell, taking some
with it. The
the proteins in the
10 Maturation: The protease enzyme finishes cutting
HIV protein chains into individual proteins that combine to
make a new working virus.
free of the
Reviewed April 27, 2007