Research
HuR interacts with human immunodeficiency virus type 1 reverse transcriptase, and modulates reverse transcription in infected cells
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* Corresponding authors: Richard Benarous richard.benarous@inserm.fr - Lang X Liu langxialiu@gmail.com
1 Institut Cochin, Université Paris Descartes, CNRS (UMR8104), Paris, France
2 Inserm, U567, Paris, France
3 Architecture et réactivité de l'ARN, UPR 9002 CNRS, 15 rue René Descartes, 67084 Strasbourg, France
4 Hybrigenics S.A., F-75014 Paris, France
5 current address : University Children's Hospital, Division of Immunology, Steinwiesstrasse 75, CH-8032, Zürich, Switzerland
6 current address : CellVir, 4 rue Pierre Fontaine, 9100 Evry, France
7 Current Address: Institutes of Life and Health Engineering, Jinan University, 601 Huang Pu Avenue West, Guangzhou 510632, China.
Retrovirology 2008, 5:47 doi:10.1186/1742-4690-5-47
Published: 10 June 2008Abstract
Reverse transcription of the genetic material of human immunodeficiency virus type 1 (HIV-1) is a critical step in the replication cycle of this virus. This process, catalyzed by reverse transcriptase (RT), is well characterized at the biochemical level. However, in infected cells, reverse transcription occurs in a multiprotein complex – the reverse transcription complex (RTC) – consisting of viral genomic RNA associated with viral proteins (including RT) and, presumably, as yet uncharacterized cellular proteins. Very little is known about the cellular proteins interacting with the RTC, and with reverse transcriptase in particular. We report here that HIV-1 reverse transcription is affected by the levels of a nucleocytoplasmic shuttling protein – the RNA-binding protein HuR. A direct protein-protein interaction between RT and HuR was observed in a yeast two-hybrid screen and confirmed in vitro by homogenous time-resolved fluorescence (HTRF). We mapped the domain interacting with HuR to the RNAse H domain of RT, and the binding domain for RT to the C-terminus of HuR, partially overlapping the third RRM RNA-binding domain of HuR. HuR silencing with specific siRNAs greatly impaired early and late steps of reverse transcription, significantly inhibiting HIV-1 infection. Moreover, by mutagenesis and immunoprecipitation studies, we could not detect the binding of HuR to the viral RNA. These results suggest that HuR may be involved in and may modulate the reverse transcription reaction of HIV-1, by an as yet unknown mechanism involving a protein-protein interaction with HIV-1 RT.