Related Experiment Video

Updated: Jul 10, 2026

Engineering and Evolution of Synthetic Adeno-Associated Virus (AAV) Gene Therapy Vectors via DNA Family Shuffling
21:55

Engineering and Evolution of Synthetic Adeno-Associated Virus (AAV) Gene Therapy Vectors via DNA Family Shuffling

Published on: April 2, 2012

Expression of AAV Rep proteins in SV40-transformed and untransformed cells: reciprocal interaction with host DNA

R B Batchu1, M A Shammas, J Y Wang

  • 1Myeloma and Transplantation Research Center, University of Arkansas for Medical Sciences, Little Rock, Ark 72205, USA.

Intervirology
|October 31, 2001
PubMed

Insights

Adeno-associated virus (AAV) Rep protein expression, normally dependent on helper viruses, occurs at low levels in simian virus 40 (SV40) transformed cells. Host DNA synthesis, not helper virus presence, elicits Rep protein production.

Area of Science:

  • Molecular Biology
  • Virology
  • Cell Biology

Background:

  • Adeno-associated virus (AAV) Rep proteins normally require helper viruses for synthesis.
  • Simian virus 40 (SV40) large T antigen induces host DNA synthesis.
  • AAV Rep proteins inhibit SV40-induced host DNA synthesis.

Purpose of the Study:

  • Investigate the interaction between SV40 T antigen and AAV Rep protein expression.
  • Determine the factors regulating AAV Rep protein synthesis in SV40-transformed cells.
  • Clarify the relationship between host DNA synthesis and AAV Rep expression.

Main Methods:

  • Utilized cell lines transformed with various SV40 T antigen mutants.
  • Measured Rep protein production in the absence of helper virus.
  • Assessed the impact of DNA synthesis inhibitors (hydroxyurea, aphidicolin) on Rep protein levels.

Main Results:

  • Observed low-level Rep protein expression in SV40-transformed cells without helper virus.
  • Rep protein expression correlated with the level of SV40-induced host DNA synthesis.
  • Inhibitors of DNA synthesis significantly reduced Rep protein levels in both immortal and normal cells.

Conclusions:

  • AAV Rep protein expression is dependent on host DNA synthesis, not solely on helper virus presence.
  • Host DNA synthesis may elicit AAV Rep gene expression, despite Rep's inhibitory role in cell cycling.
  • SV40 T antigen's ability to induce host DNA synthesis indirectly influences AAV Rep expression.

More Related Videos

Transgene Expression in Cultured Cells Using Unpurified Recombinant Adeno-Associated Viral Vectors06:41

Transgene Expression in Cultured Cells Using Unpurified Recombinant Adeno-Associated Viral Vectors

Published on: October 20, 2023

Electrophoretic Analysis of Replication Through Structure-Prone DNA Repeats Within the SV40-Based Human Episome05:22

Electrophoretic Analysis of Replication Through Structure-Prone DNA Repeats Within the SV40-Based Human Episome

Published on: September 13, 2024

Related Concept Videos

Retrovirus Life Cycles01:10

Retrovirus 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...
Viral Recombination00:57

Viral Recombination

Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
Retroviruses02:33

Retroviruses

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’...
Mechanisms of Retrovirus-induced Cancers01:51

Mechanisms 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...
Rous Sarcoma Virus (RSV) and Cancer01:03

Rous 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...
Size and Structure of Viral Genomes01:26

Size 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...