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cytoplasm the material in a cell, excluding the nucleus

apoptosis programmed cell death

_HIV

LIFE CYCLE OF HIV AND SITE OF ACTION OF ANTI-HIV DRUGS

reverse transcriptase reverse transcriptase

CD4 receptor

genome RNA .

genome RNA .

messenger RNA

-^i—- proteins messenger RNA

HIV binds to CD4 and CCR-5 or CXCR4 on the surface of the target cell, allowing the virus coat to fuse with the cell membrane and virus contents to enter the cell. (2) Reverse transcriptase (RT) enzyme transcribes viral RNA into singlestrand viral DNA, a step blocked by RT inhibitors (AZT, ddi, d4t, ddc). Single-strand DNA is converted to double-strand DNA which then enters the nucleus and integrates into the host chromosome. (3) Upon activation of the cell, viral RNA triggers manufacture of viral proteins. In the absence of protease inhibitors, proteins are processed into shorter lengths. Protease inhibitors (saquinavir, ritonavir, indinavir, nelfinavir) prevent this step, interrupting the viral life cycle. (4) After all components are present in the cell, HIV particles assemble and bud from the cell. Adapted from Stine, 1997.

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