UNC Scientists Succeed In Inserting Gene In Human Cells Via Artificial Chromosome

August 31, 1998

CHAPEL HILL--Using a promising new technique, University of North Carolina at Chapel Hill scientists have for the first time successfully inserted large circular plasmids - doughnut-shaped pieces of DNA containing healthy genes - into human cells and showed the genes functioned as if they belonged there. After more than a year, the genes continued to operate normally.

The work is important, researchers say, because it may offer a more effective method of transferring healthy genes into humans with various illnesses such as hemophilia, cystic fibrosis and sickle cell anemia and improve treatment.

"We have been able to do this with a piece of DNA five to 20 times the usual size scientists work with," said Dr. Jean Michel Vos, associate professor of biochemistry at the UNC-CH School of Medicine. "Although so far we have worked only in cultured human cells in the laboratory, we believe it could eventually work well directly in humans. It is exciting and very promising."

A report on the research appears in the September issue of Human Gene Therapy, a scientific journal. Besides Vos, authors are Drs. Eva Maria Westphal, postdoctoral fellow in medicine; Halina Sierakowska, postdoctoral fellow in biochemistry; and Ryszard Kole, associate professor of pharmacology; and technician Elisabeth Livanos, all of the UNC Lineberger Comprehensive Cancer Center.

Researchers transferred genes responsible for producing Beta-globin, one of two chief components of hemoglobin, the large molecule that carries oxygen in blood. Each time their cultured human cells divided, the genes replicated, or reproduced, as well and functioned for more than a year.

"You can think of it as an artificial chromosome," Vos said. "It does not become part of any of the 46 original chromosomes in each cell nucleus by inserting itself into them, but it is in addition to them."

In collaboration with Kole's laboratory, Vos and Westphal also showed the genes to be active, going from double-stranded DNA to single strands of RNA, the first step toward production of protein, which is the genes' purpose. DNA and RNA are like molecular blueprints for protein production.

Bacteria first are used, like little factories, to clone DNA outside the human cells because bacteria take only an hour to reproduce rather than the 24 hours human cells require.

The scientists then attach the DNA in circular form to a harmless part of the Epstein-Barr virus because of the virus' ability to replicate and maintain itself in the nucleus of human cells. The virus serves as a vector, or carrier, of the human genes, something like attaching a locomotive to freight cars to take them where they are needed.

By creating separate, artificial chromosomes, researchers no longer have to worry about genes they are transferring attaching randomly to parts of other chromosomes and then not working independently, Westphal said. The circular design promotes strength and stability because linear forms have a greater tendency to break inside the cell nucleus.

"I want to stress that this work is not a gene therapy cure for any disease yet, but I do think it is a major technical step forward," Vos said. "It moves the field from working with shrunken versions of human genes to entire functioning genes. We have shown the genes function and function for a long time."

Three years ago, Vos and colleagues published a paper in Nature Genetics suggesting it would be possible to build a circular artificial chromosome. In August they published another paper in Nature Biotechnology showing how to build artificial chromosomes in mouse cells, a step before doing it in whole animals.

The U.S. Department of Energy and the Bayer Corp. supported the research, along with help from faculty and staff at the Roosevelt Park Cancer Center in Buffalo, N.Y., the Murdoch Institute in Melbourne, Australia, and Glaxo-Wellcome in Research Triangle Park.

By David Williamson

Note: Vos can be reached at (919) 966-8644 or 966-6887, Westphal at 966-1248 and Kole at 966-1143.

Contact: David Williamson, (919) 962-8596, or Bret Johnson, 962-0352.

University of North Carolina at Chapel Hill

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.