Related Experiment Video
Updated: Aug 5, 2026
07:18
High Throughput In Vitro Assessment of Latency Reversing Agents on HIV Transcription and Splicing
Published on: January 22, 2019
The HIV-1 restriction factor RPRD2 does not inhibit transcription of HIV-1 or endogenous retroelements
Kathryn A Jackson-Jones1,2, Hui Xin Loh1, Arda Tarcan1
1Institute for Regeneration and Repair, Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK.
Biorxiv : the Preprint Server for Biology
|August 1, 2026
Summary
The protein RPRD2 regulates host gene transcription but does not affect HIV-1 provirus or endogenous retroelement transcription, despite its known role as an HIV restriction factor.
Area of Science:
- Molecular Biology
- Virology
- Gene Regulation
Background:
- RPRD2 is known as an HIV restriction factor inhibiting reverse transcription.
- RPRD2 also regulates global transcription of host genes.
- The differential regulation of viral, episomal, and endogenous DNA transcription versus host genes is a key question.
Purpose of the Study:
- To investigate whether RPRD2 regulates nascent transcription from HIV provirus and endogenous retroelements.
- To characterize the binding of RPRD2 to RNA and DNA:RNA hybrids.
- To determine RPRD2's effect on transcription of various DNA species.
Main Methods:
- Experimental and computational methods to characterize RPRD2 binding to RNA and DNA:RNA hybrids.
- Immunoprecipitation to identify RPRD2 interacting partners (PAF1, TASOR).
- Immunofluorescence for RPRD2 localization.
- Reporter gene assays using plasmid-borne HIV LTR constructs.
- Analysis of transcription from integrated proviruses and endogenous retroelements (LINE-1, HERV-K).
- Assessment of RPRD2's effect on interferon (IFN) production and IFN-stimulated genes (ISGs).
Main Results:
- RPRD2 interacts with transcription regulator PAF1 and HUSH complex member TASOR.
- RPRD2 localizes to nuclear speckles.
- RPRD2 depletion increased transcription from plasmid-borne HIV LTR reporter constructs.
- RPRD2 depletion had no effect on transcription from integrated HIV proviruses.
- RPRD2 depletion did not affect transcription of endogenous retroelements (LINE-1, HERV-K).
- RPRD2 depletion did not affect IFN production or ISG expression.
Conclusions:
- Transcription regulation is not universal across different DNA species (host genes, integrated provirus, plasmids, endogenous retroviruses).
- RPRD2 regulates cellular transcription but not the transcription of HIV-1 provirus or endogenous retroelements.
- RPRD2's role as an HIV restriction factor may not involve direct regulation of proviral transcription.
Related Concept Videos
01:10Retrovirus Life Cycles
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
02:33Retroviruses
Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...
03:08LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
01:29Viruses with RNA Genomes
RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
01:26Size and Structure of Viral Genomes
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
01:25Inhibitors Of Virion Release
Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...