Newly generated heparanase knock-out mice unravel co-regulation of heparanase and matrix metalloproteinases.

Background: Heparanase, a mammalian endo-beta-D-glucuronidase, specifically degrades heparan sulfate proteoglycans ubiquitously associated with the cell surface and extracellular matrix. This single gene encoded enzyme is over-expressed in most human cancers, promoting tumor metastasis and angiogenesis.

Principal Findings: We report that targeted disruption of the murine heparanase gene eliminated heparanase enzymatic activity, resulting in accumulation of long heparan sulfate chains.

Abrogation of Vif function by peptide derived from the N-terminal region of the human immunodeficiency virus type 1 (HIV-1) protease.

The human immunodeficiency virus type 1 (HIV-1) auxiliary gene vif is essential for virus propagation in peripheral blood lymphocytes, macrophages, and in some T-cell lines. Previously, it was demonstrated that Vif inhibits the autoprocessing of truncated HIV-1 Gag-Pol polyproteins expressed in bacterial cells, and that purified recombinant Vif and Vif-derived peptides inhibit and bind HIV-1 protease (PR). Here we show that Vif interacts with the N-terminal region of HIV-1 PR, and demonstrate that peptide derived from the N-terminal region of PR abrogates Vif function in non-permissive cells.

Electronic transduction of HIV-1 drug resistance in AIDS patients.

A drug composition consisting of nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs) is commonly used in AIDS therapy. A major difficulty encountered with the therapeutic composite involves the emergence of drug-resistant viruses, especially to the PIs, regarded as the most effective drugs in the composition. We present a novel bioelectronic means to detect the appearance of mutated HIV-1 exhibiting drug resistance to the PI saquinavir.

The Vif protein of human immunodeficiency virus type 1 (HIV-1): enigmas and solutions.

HIV-1 and other complex retroviruses express six auxiliary genes in addition to the canonical retroviral genes, gag, pol and env. Vif (virion infectivity factor) protein is absolutely essential for productive HIV-1 infection of peripheral blood lymphocytes and macrophages, the two major HIV-1 target cells in vivo. However, Vif is not required for production of infectious particles in several human cell lines.

Human immunodeficiency virus type 1 Vif binds the viral protease by interaction with its N-terminal region.

The vif gene, one of the six auxiliary genes of human immunodeficiency virus (HIV), is essential for virus propagation in peripheral blood lymphocytes and macrophages and in certain T-cell lines. Previously, it was demonstrated that Vif inhibits the autoprocessing of truncated HIV type 1 (HIV-1) Gag-Pol polyproteins expressed in bacterial cells, as well as the protease-mediated cleavage of synthetic peptides in vitro. Peptides derived from the aa 78-98 region in the Vif molecule specifically inhibit and bind the HIV-1 protease in vitro and arrest the production of infectious viruses in HIV-1-infected cells.

HIV-1 Vif-derived peptide inhibits drug-resistant HIV proteases.

Vif, one of the six accessory genes expressed by HIV-1, is essential for the productive infection of natural target cells. Previously we suggested that Vif acts as a regulator of the viral protease (PR): It prevents the autoprocessing of Gag and Gag-Pol precursors until virus assembly, and it may control the PR activity in the preintegration complex at the early stage of infection. It was demonstrated before that Vif, and specifically the 98 amino acid stretch residing at the N'-terminal part of Vif (N'-Vif), inhibits both the autoprocessing of truncated Gag-Pol polyproteins in bacterial cells and the hydrolysis of synthetic peptides by PR in cell-free systems.