Lisa Ivanoff

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The genome of the human immunodeficiency virus HIV-1 contains at least eight genes, of which three (sor, R, and 3' orf) have no known function. In this study, the role of the sor gene was examined by constructing a series of proviral genomes of HIV-1 that either lacked the coding sequences for sor or contained point mutations in sor. Analysis of four such(More)
BACKGROUND Development of alcohol dependence, a chronic and relapsing disease, largely depends on the effects of alcohol on the brain reward systems. By elucidating the mechanisms involved in alcohol use disorder, novel treatment strategies may be developed. Ghrelin, the endogenous ligand for the growth hormone secretagogue receptor 1A, acts as an important(More)
We have engineered a segment of the poliovirus genome (nucleotides 5438-6061) that encodes the 183 amino acid residues of the 3C region and 25 residues of the 3D region of the viral polyprotein into an Escherichia coli expression vector. The 3C region is a virus-specific protease, which, when expressed in E. coli, is shown to be active and autocatalytic. In(More)
(2R,4S,5S,1'S)-2-Phenylmethyl-4-hydroxy-5-(tert-butoxycarbonyl) amino-6-phenylhexanoyl-N-(1'-imidazo-2-yl)-2'-methylpropanamide (compound 2) is a tripeptide analogue inhibitor of HIV-1 protease in which a C-terminal imidazole substituent constitutes an isoelectronic, structural mimic of a carboxamide group. Compound 2 is a potent inhibitor of the protease(More)
Antiviral activities of known protease inhibitors were assayed in virus-infected cell cultures. Some members of the cystatin superfamily, in particular chicken cystatin, were able to block virus replication. In a binding assay, using purified components, chicken and human cystatin were able to bind poliovirus protease with affinities which were reflected in(More)
The mechanism by which HIV-1 mediates cell fusion and penetrates target cells, subsequent to receptor (CD4) binding, is not well understood. However, neutralizing antibodies, which recognize the principal neutralizing determinants of the gp120 envelope protein (the V3 loop region, residues 296 to 331), have been shown to effectively block cell fusion and(More)
The poliovirus polymerase 3D was synthesized in Escherichia coli by cleavage of fusion proteins expressed from cloned viral cDNA inserted into several plasmid expression vectors. Cleavage was accomplished by the action of viral protease 3C sequences expressed in the same bacteria, either from a second plasmid or from the same plasmid, cloned so as to(More)
The V3 loop (residues 303-338) of the human immunodeficiency virus type 1 (HIV-1) gp120 envelope protein represents a principal neutralizing determinant for the virus. An HIV-1 proviral clone containing a mutation in the V3 loop was constructed in which the proline residue at position 313 was changed to an alanine (P313-A). This mutation alters the(More)
Proviral clones of human immunodeficiency virus type 1 which contained single amino acid changes in the envelope V3 region were constructed. PCR amplification of Sup-T1 T cells transfected with one such mutant, G312T, revealed low levels of virus that resulted in the generation of a revertant virus, in which an alanine replaced the threonine residue at(More)