Human immunodeficiency virus type 1 Vif functionally interacts with diverse APOBEC3 cytidine deaminases and moves with them between cytoplasmic sites of mRNA metabolism.

Vif(IIIB), which has been a standard model for the viral infectivity factor of human immunodeficiency virus type 1 (HIV-1), binds the cytidine deaminase APOBEC3G (A3G) and induces its degradation, thereby precluding its lethal incorporation into assembling virions. Additionally, Vif(IIIB) less efficiently degrades A3F, another potent anti-HIV-1 cytidine deaminase. Although the APOBEC3 paralogs A3A, A3B, and A3C have weaker anti-HIV-1 activities and are only partially degraded by Vif(IIIB), we found that Vif(IIIB) induces their emigration from the nucleus to the cytosol and thereby causes net increases in the cytosolic concentrations and anti-HIV-1 activities of A3A and A3B.

Interaction of the tobacco mosaic virus replicase protein with the Aux/IAA protein PAP1/IAA26 is associated with disease development.

Virus-infected plants often display developmental abnormalities that include stunting, leaf curling, and the loss of apical dominance. In this study, the helicase domain of the Tobacco mosaic virus (TMV) 126- and/or 183-kDa replicase protein(s) was found to interact with the Arabidopsis Aux/IAA protein PAP1 (also named IAA26), a putative regulator of auxin response genes involved in plant development. To investigate the role of this interaction in the display of symptoms, a TMV mutant defective in the PAP1 interaction was identified.

Tobacco mosaic virus induced alterations in the gene expression profile of Arabidopsis thaliana.

In this study, mRNA profiles generated from cDNA microarrays were used to identify gene expression changes in Arabidopsis thaliana ecotype Shahdara infected with Tobacco mosaic virus (TMV). Shahdara is a susceptible TMV host, permitting rapid accumulations of virus in both inoculated and systemic tissues, accompanied by defined disease symptoms that include stunting, necrosis, and leaf curling. Gene expression profiles were monitored in whole tissues of inoculated leaves at four days postinoculation (dpi) and in systemically infected leaves at 14 dpi.

A nuclear localization signal and a membrane association domain contribute to the cellular localization of the Tobacco mosaic virus 126-kDa replicase protein.

A transient expression system using onion epidermal cells was used to investigate domains of the Tobacco mosaic virus (TMV) 126-kDa replicase protein involved in cellular localization. Initially, a nuclear localization signal (NLS), identified within the amino-terminus of the 126-kDa protein, was investigated for its functionality using fusion constructs containing the green fluorescent protein (GFP). Fusion of the amino-terminal 70 amino acids of the 126-kDa protein, containing the NLS, to a beta-glucuronidase-GFP open reading frame (ORF), directed the accumulation of fluorescence to the nucleus.