Dual effect of the SR proteins ASF-SF2, SC35 and 9G8 on HIV-1 RNA splicing and virion productionReport as inadecuate




Dual effect of the SR proteins ASF-SF2, SC35 and 9G8 on HIV-1 RNA splicing and virion production - Download this document for free, or read online. Document in PDF available to download.

Retrovirology

, 2:33

First Online: 22 May 2005Received: 02 May 2005Accepted: 22 May 2005

Abstract

In HIV-1 infected cells transcription of the integrated provirus generates the single full length 9 kb viral RNA, a major fraction of which is spliced to produce the single-spliced 4 kb RNAs and the multiple-spliced 2 kb RNAs. These spliced RNAs are the messengers for the Env glycoproteins and the viral regulatory factors. The cellular SR and hnRNP proteins were shown in vitro to control alternative splicing by binding cis-regulatory elements on the viral RNA. To better understand in vivo the role of the SR proteins on HIV-1 genomic RNA splicing and virion production, we used a human cell line expressing high levels of complete HIV-1 and either one of the ASF-SF2, SC35, and 9G8 SR proteins. Results show that over-expressing SR proteins caused a large reduction of genomic RNA and that each SR protein modified the viral 9 kb RNA splicing pattern in a specific mode. In fact, ASF-SF2 increased the level of Vpr RNA while SC35 and 9G8 caused a large increase in Tat RNA. As expected, overexpressing SR proteins caused a strong reduction of total Gag made. However, we observed by immuno-confocal microscopy an accumulation of Gag at the plasma membrane and in intracellular compartments while there is a dramatic reduction of Env protein made in most cells. Due to the negative impact of the SR proteins on the levels of genomic RNA and HIV-1 structural proteins much less virions were produced which retained part of their infectivity. In conclusion, SR proteins can down-regulate the late steps of HIV-1 replication.

Abbreviations usedHIV-1Human Immunodeficiency Virus type 1.

CAp24viral capsid protein p24.

MAp17viral matrix protein p17.

RTreverse transcriptase.

SRsplicing regulatory proteins.

hnRNP proteinsheterogenous ribonucleoparticle proteins.

Site Asplicing acceptor site. Site D, splicing donor site.

Kbkilobases. WT, wild type.

PBSPhosphate Buffer Saline.

BSAbovine serum albumin.

Mabmonoclonal antibody.

Electronic supplementary materialThe online version of this article doi:10.1186-1742-4690-2-33 contains supplementary material, which is available to authorized users.

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Author: Sandrine Jacquenet - Didier Decimo - Delphine Muriaux - Jean-Luc Darlix

Source: https://link.springer.com/







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