The aim of this proposal is to characterize the process of SIV envelope glycoprotein incorporation into budding particles, the step in SIV morphogenesis that confers infectivity to virions. The specific incorporation of envelope protein into the virion has been proposed to occur through an interaction between its cytoplasmic domain and the matrix domain of the Gag polyprotein. The PI proposes to map the domains in both SIV matrix and the envelope cytoplasmic tail whose interaction mediates the association of the envelope protein with virions. These studies will permit a better understanding of a key step in the SIV life cycle and may be useful for rational design of strategies aimed at blocking the infectivity of the closely related HIV-1 and HIV-2 viruses. There are three specific aims.
In Aim 1, the PI will analyze the effect of existing and additional novel amino acid substitutions in the SIV matrix protein on virion assembly, viral glycoprotein incorporation and virus infectivity through targeted mutagenesis of the N-terminal third of the SIV MA protein.
In aim 2, domains of the SIV TM cytoplasmic tail required for envelope association with virus particles will be mapped, using SIV genomes with MA mutations and encoding truncations, deletions and substitutions in their TM proteins. These viruses will be evaluated for viral infectivity and levels of particle associated envelope glycoprotein.
The third aim will be to develop an in vitro system for defining protein-protein interactions between SIV MA and SIV TM using a GST-tagged, baculovirus-expressed cytoplasmic domain of SIV to quantitate interactions with MA.
| Celma, Cristina C P; Manrique, Julieta M; Hunter, Eric et al. (2004) Second-site revertants of a simian immunodeficiency virus gp41 mutant defective in envelope glycoprotein incorporation. AIDS Res Hum Retroviruses 20:733-41 |
| Celma, C C; Manrique, J M; Affranchino, J L et al. (2001) Domains in the simian immunodeficiency virus gp41 cytoplasmic tail required for envelope incorporation into particles. Virology 283:253-61 |
