HIV Research Today is a free monthly online journal that collates and summarizes the latest research about HIV, including details on human immunodeficiency virus, testing, treatment, prevention, vaccines, aids.

Transient and stable knockdown of the integrase cofactor LEDGF/p75 reveals its role in the replication cycle of human immunodeficiency virus.

Vandekerckhove L, Christ F, Van Maele B, De Rijck J, Gijsbers R, Van den Haute C, Witvrouw M, Debyser Z

Molecular Medicine, K.U.Leuven and IRC KULAK, Kapucijnenvoer 33, B-3000 Leuven, Flanders, Belgium.

After identifying the interaction between the transcriptional coactivator lens epithelium-derived growth factor (LEDGF/p75) and the human immunodeficiency virus type 1 (HIV-1) integrase (IN), we have now investigated the role of LEDGF/p75 during HIV replication. Transient small interfering RNA-mediated knockdown of LEDGF/p75 in HeLaP4 cells resulted in a three- to fivefold inhibition of HIV-1 (strain NL4.3) replication. Quantitative PCR was used to pinpoint the replication block to the integration step. Next, polyclonal and monoclonal HeLaP4-derived cell lines were selected with a stable knockdown of LEDGF/p75 mediated by a lentiviral vector (lentivector) encoding a short hairpin RNA (shRNA) targeting this protein. Cell lines stably transduced with a lentivector encoding an unrelated hairpin or a double-mismatch hairpin served as controls. Again, a two- to fourfold reduction of HIV-1 replication was observed. The extent of LEDGF/p75 knockdown closely correlated with the reduction of HIV-1 replication. After the back-complementation of LEDGF/p75 in the poly- and monoclonal knockdown cell lines using an shRNA-resistant expression plasmid, viral replication was restored to nearly wild-type levels. The Q168A mutation in integrase has been shown to interfere with the interaction with LEDGF/p75 without reducing the enzymatic activity. Transduction by HIV-1-derived lentivectors carrying the Q168A IN mutant was severely hampered, pointing again to a requirement for LEDGF/p75. Altogether, our data validate LEDGF/p75 as an important cellular cofactor for HIV integration and as a potential target for antiviral drug development.

Published 27 January 2006 in J Virol, 80(4): 1886-96.
Full-text of this article is available online (may require subscription).

© 2004-2008 HIV Research Today. All Rights Reserved.