Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Genetic trick adapted from viruses makes gene therapy vectors more versatile


Gene cassettes using self-cleaving peptides allowed T lymphocytes to construct a key multi-protein immune receptor complex

A genetic trick used by viruses to replicate themselves has been adapted for laboratory use to build complex protein structures required by immune system cells, according to investigators at St. Jude Children’s Research Hospital.

This approach could also be used to develop new gene therapy vectors in cases when cells must be modified to make high levels of different proteins. A vector is a DNA molecule used to ferry specific genes into cells in order to give those cells the ability to make particular proteins.

A report on this work appears in the May 2004 issue of Nature Biotechnology.

The achievement gives researchers a powerful tool for studying the roles of complex proteins in living cells. The study also showed that this technique can reliably produce therapeutically useful amounts of multiple proteins. Some cellular proteins must be present in many copies in order to work efficiently. Because it only borrows a genetic trick from viruses but does not cause a real infection, the technique may increase the usefulness of current gene therapy vectors. Specifically, the technique would permit scientists either to restore complex protein structures that are missing in certain cells or make multiple proteins that act together as potent drugs against cancer and other diseases.

The technique is based on a genetic trick, called a self-cleaving 2A peptide, which is used by some viruses to produce multiple proteins from a single length of DNA; i.e., a single, long protein is produced that automatically breaks into multiple, distinct proteins.

St. Jude researchers used genetically modified mouse immune system cells called T lymphocytes to test the efficiency of this technique in making the CD3 complex, which is part of the T cell receptor, a large protein lodged in the cell’s membrane. The receptor allows T cells to "sense" targets that the cells are programmed to destroy. Without the CD3 complex, the T cell receptor is incomplete and cannot perform its immune function.

The St. Jude researchers used retroviral vectors as the delivery system into which they inserted cassettes (groups of genes) that contained genes for the four CD3 proteins, separated by the 2A peptides. These 2A peptides acted like cleavers to break apart the long protein into the four different, smaller CD3 proteins. The cell used these smaller proteins to build the large TCR:CD3 receptor. In order to replicate inside a cells, the retrovirus RNA must first be changed back into DNA. A retrovirus is a virus whose genetic material is RNA instead of DNA.

The St. Jude team used these multicistronic retroviral vectors (vectors carrying several different genes) to deliver the 2A peptide-linked CD3 gene cassettes into hematopoietic stem cells from mice that lacked the CD3 proteins, and thus could not make T cells. These genetically modified stem cells subsequently developed and restored T cell development in the mice. Hematopoietic stem cells are "parent" cells that give rise to all the red and white cells found in blood.

"These 2A peptides will allow us, and others, to generate single vectors that can efficiently and reliably express multiple proteins in the exact amounts needed to permit the cell to assemble complex structures," said Dario A. A. Vignali, Ph.D., associate member of the St. Jude Department of Immunology and a faculty member at the University of Tennessee Medical Center. Vignali is senior author of the Nature Biotechnology report.

"We expect that this technique will make it a lot easier for us to study the role of complex protein structures," Vignali said. "These 2A peptides may also facilitate the development of more versatile gene therapy vectors for treatments that require replacement or expression of more than a single gene."

Other authors of this study are Andrea L. Szymczak (St. Jude and University of Tennessee), Creg J. Workman, Yao Wang, Kate M. Vignali, Smaroula Dilioglou (St. Jude) and Elio F. Vanin (currenly Baylor College of Medicine.)

This work was supported in part by NIH, a Cancer Center Support (CORE) grant and ALSAC.

St. Jude Children’s Research Hospital
St. Jude Children’s Research Hospital is internationally recognized for its pioneering work in finding cures and saving children with cancer and other catastrophic diseases. Founded by late entertainer Danny Thomas and based in Memphis, Tennessee, St. Jude freely shares its discoveries with scientific and medical communities around the world. No family ever pays for treatments not covered by insurance, and families without insurance are never asked to pay. St. Jude is financially supported by ALSAC, its fundraising organization. For more information, please visit

Bonnie Cameron | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>