Related Experiment Video
Updated: Jul 19, 2026
09:31
Amplification, Next-generation Sequencing, and Genomic DNA Mapping of Retroviral Integration Sites
Published on: March 22, 2016
Alternate polypurine tracts affect rous sarcoma virus integration in vivo
Jangsuk Oh1, Kevin W Chang, W Gregory Alvord
1HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
Journal of Virology
|September 29, 2006
Summary
Replacing the polypurine tract (PPT) in Rous sarcoma virus (RSV) vectors alters viral DNA processing. Aberrant U3 LTR termini lead to incorrect integration, causing host DNA duplications or deletions instead of normal insertions.
Area of Science:
- Molecular Biology
- Virology
- Retroviral Research
Background:
- The polypurine tract (PPT) is crucial for retroviral DNA replication and integration.
- Rous sarcoma virus (RSV) vectors are widely used tools in molecular biology and gene delivery.
- Understanding retroviral DNA processing is key to improving gene therapy vectors.
Purpose of the Study:
- To investigate the impact of replacing the endogenous PPT in RSV-derived vectors with alternate PPTs.
- To examine how alterations in the U3 long terminal repeat (LTR) terminus affect viral DNA processing and integration.
- To elucidate the role of the canonical CA in joining aberrant U3 LTRs to host DNA.
Main Methods:
- RSVP(A)Z vectors with modified PPT sequences were constructed.
- Analysis of unintegrated viral DNA to assess processing and end integrity.
- Investigation of viral integration into host genomes with aberrant U3 LTR termini.
Main Results:
- Replacing the endogenous PPT significantly decreased viral DNA with normal consensus ends.
- Retention of partial PPT sequences increased when alternate PPTs were used.
- RSV integrase could process and integrate normal U5 LTRs even with aberrant U3 LTR termini.
- The canonical CA was not involved in joining aberrant U3 LTRs, leading to host sequence duplications or deletions.
Conclusions:
- The PPT sequence critically influences the processing of viral DNA ends.
- Aberrant U3 LTR termini disrupt normal integration, resulting in genomic instability.
- RSV integrase exhibits flexibility in processing but canonical CA is essential for precise integration at aberrant sites.
Related Concept Videos
01:03Rous Sarcoma Virus (RSV) and Cancer
Rous Sarcoma virus or RSV was discovered by F. Peyton Rous in the year 1911 as a filterable transmissible agent that could cause tumors in chickens. He won a Nobel Prize for this discovery in 1966. His experiments clearly demonstrated that some cancers could be caused by infectious agents and led to the discovery of many more cancer-causing viruses in animals as well as humans.
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
01:03Rous Sarcoma Virus (RSV) and Cancer
Rous Sarcoma virus or RSV was discovered by F. Peyton Rous in the year 1911 as a filterable transmissible agent that could cause tumors in chickens. He won a Nobel Prize for this discovery in 1966. His experiments clearly demonstrated that some cancers could be caused by infectious agents and led to the discovery of many more cancer-causing viruses in animals as well as humans.
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
RSV is a retrovirus that contains two copies of a plus-strand RNA genome. Its genome consists of four main open...
01:51Mechanisms of Retrovirus-induced Cancers
Retroviruses are RNA viruses that have been shown to cause cancers in diverse species, including chickens, mice, cats, and monkeys. The RNA genomes of these viruses are first reverse-transcribed into single and then double-stranded DNA (dsDNA) copies. This dsDNA called proviral DNA then integrates into the host genome. Subsequently, the host cell transcribes the proviral DNA in concert with the chromosomal DNA. This leads to the production of viral RNA and proteins that assemble at the host...
01:51Mechanisms of Retrovirus-induced Cancers
Retroviruses are RNA viruses that have been shown to cause cancers in diverse species, including chickens, mice, cats, and monkeys. The RNA genomes of these viruses are first reverse-transcribed into single and then double-stranded DNA (dsDNA) copies. This dsDNA called proviral DNA then integrates into the host genome. Subsequently, the host cell transcribes the proviral DNA in concert with the chromosomal DNA. This leads to the production of viral RNA and proteins that assemble at the host...
03:18Non-LTR Retrotransposons
As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
02:57piRNA - Piwi-interacting RNAs
PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while only 2000 genes have been found for miRNAs. piRNAs can act at the transcriptional and post-transcriptional levels and have a vital role in silencing transposable elements present in germ cells. They are also involved in epigenetic silencing and activation. Previously, they were thought to function only in germ cells but new evidence suggests...