AEGiS-14IAC: Maturation of HIV virions.

14th International AIDS Conference


Barcelona, Spain - July 7-12, 2002

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Maturation of HIV virions.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. WeOrA1261)

Bukrinskaya AG, Stevenson M
University of Massachusetts Medical School, Worcester, United States

BACKGROUND: HIV-1 particle assembly is directed by the GAG proteins which are initially synthesized as a polyprotein p55 which is cleaved by virus-encoded protease to produce mature GAG proteins. Dramatic morphological changes occur inside the released virions which lead to the appearance of a cone-shaped capsid. Although important information has been obtained about virus assembly, it is not defined how the described processes correlate with virion infectivity. We studied kinetics of virus maturation with regard to RT activity, protein composition, density in sucrose gradients and infectivity in MAGI cells.

METHODS: Supernatants from HIV-1 transfected 293 T cells were taken every 4 hours after transfection. The virus was pelleted by centrifugation and purified by centrifugation in 20-60% sucrose gradients. RT activity of purified virus was measured and the infectivity of the virus normalized to equal RT was determined in MAGI cells. Viral proteins were analyzed by Western blotting.

RESULTS: RT activity of the virus increased progressively from 12 to 36 hours after cell transfection and then gradually decreased. The virus density in sucrose gradients increased from 1.14 g/ml in the samples taken from 12 to 16 hours after transfection to 1.15 at 20hours and at 24 hours to 1.16 g/ml. The virus collected before 20 hours was poorly infectious while virus normalize to the same RT collected at later intervals was highly infectious in MAGI cells. However, the marked change in infectivity did not reflect similar differences in the level of processed and precursor virion proteins.

CONCLUSION: Our results demonstrate a significant change in virus infectivity that does not show an obvious correlation with the processing of precursor proteins. This suggests a step in virus assembly independent to precursor maturation that impacts the infectivity of the virion.

Keywords: AEGIS, HIV, Virion, Gene Products, gag, HIV Infections, HIV-1, Virus Assembly, HIV Seropositivity, HIV Protease Inhibitors, Capsid, Viral Proteins, Blotting, Western, Transfection, virology, geneticsKWDaegis,hiv,virion,geneproducts,gag,hivinfections,hiv-1,virusassembly,hivseropositivity,hivproteaseinhibitors,capsid,viralproteins,blotting,western,transfection,virology,genetics

020707
WeOrA1261

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