Antagonism to human BST-2/tetherin by Sendai virus glycoproteins.

Tetherin is an interferon-inducible factor that restricts viral particle production. We show here that Sendai virus (SeV) induces a drastic decrease in tetherin levels in infected HeLa cells. Using ectopic expression of tetherin in Madin-Darby canine kidney cells, we find that infectious SeV production is sensitive to restriction by tetherin, suggesting that SeV downregulates tetherin to counter this form of cellular restriction.

The cellular protein TIP47 restricts Respirovirus multiplication leading to decreased virus particle production.

The cellular tail-interacting 47-kDa protein (TIP47) acts positively on HIV-1 and vaccinia virus production. We show here that TIP47, in contrast, acts as a restriction factor for Sendai virus production. This conclusion is supported by the occurrence of increased or decreased virus production upon its suppression or overexpression, respectively.

Nucleotide excision repair and template-independent addition by HIV-1 reverse transcriptase in the presence of nucleocapsid protein.

During HIV replication, reverse transcriptase (RT), assisted by the nucleocapsid protein (NC), converts the genomic RNA into proviral DNA. This process appears to be the major source of genetic variability, as RT can misincorporate nucleotides during minus and plus strand DNA synthesis. To investigate nucleotide addition or substitution by RT, we set up in vitro models containing HIV-1 RNA, cDNA, NC, and various RTs.

The chaperoning and assistance roles of the HIV-1 nucleocapsid protein in proviral DNA synthesis and maintenance.

In the following three sections, we will briefly review the seminal roles of the HIV-1 nucleocapsid protein p7 (NCp7) in the fate of the HIV-1 full length RNA from genomic RNA in a dimeric form to the proviral DNA. Emphasis will be given to the mechanisms of NC-directed assistance to the genomic RNA and reverse transcriptase (RT) in the course of proviral DNA synthesis and to DNA integrity at the end of the polymerization process, and to the NC-assisted repair and recombination reactions fueling the viability and variability of the virus.

The chaperoning and assistance roles of the HIV-1 nucleocapsid protein in proviral DNA synthesis and maintenance.

In the following three sections we will briefly review the seminal roles of the HIV-1 nucleocapsid protein NCp7 in the fate of the HIV-1 full length RNA from genomic RNA in a dimeric form to the proviral DNA. Emphasis will be given to the mechanisms of NC-directed assistance to the genomic RNA and reverse transcriptase in the course of proviral DNA synthesis and to DNA integrity at the end of the polymerization process, and to the NC-assisted repair and recombination reactions fueling the viability and variability of the virus.

A 5'-3' long-range interaction in Ty1 RNA controls its reverse transcription and retrotransposition.

LTR-retrotransposons are abundant components of all eukaryotic genomes and appear to be key players in their evolution. They share with retroviruses a reverse transcription step during their replication cycle. To better understand the replication of retrotransposons as well as their similarities to and differences from retroviruses, we set up an in vitro model system to examine minus-strand cDNA synthesis of the yeast Ty1 LTR-retrotransposon.