New technique for rapidly identifying the functions of genes

The "high throughput" technique can be used in both cell culture and in animal models to screen thousands of genes for a particular biological function. It provides a method for the rapid development of a cDNA library, which would contain protein-encoding sequences of DNA. Researchers then can use the library to analyze a specific gene function.

The report appears in the July issue of Molecular Therapy, the American Society of Gene Therapy’s journal.

"All the genes in the human genome have now been sequenced, but the problem is that we don’t know their function," said Dr. Tal Kafri, principal investigator of the study and an assistant professor of microbiology and immunology at UNC’s School of Medicine. He also is a member of the UNC Gene Therapy Center.

The study helps to resolve two bottlenecks in determining gene functions, he said.

"It offers a quick and efficient way to transfer cDNA into a viral vector library, and it also helps isolate altered cells, ensuring that the changes in them are due to the introduced gene. The closed system we have developed allows us to take candidate genes from virus to bacteria to cell to animal, quickly and efficiently."

The technique system may have clinical applications, including drug design, Kafri added.

"We could easily modify the library to find peptides or small molecules with potential to act as inhibitors for a particular cellular state or pathway. Doing so would drastically accelerate the process of high-throughput drug design and testing, taking gene candidates from cell culture to the animal model."

The technique uses a genetically engineered HIV-1 virus, in which genes can be shuttled among bacteria, cell culture or animal models, in the same vehicle, or vector. This avoids time-consuming methods involved in gene isolation and amplification, such as the polymerase chain reaction, or PCR, procedure.

The method, designed by Kafri and gene therapy center researcher Hong Ma, enables scientists to rapidly screen cells for changes in a particular phenotype. They can easily isolate and identify the gene causing the changes and place it into an animal model or bacteria for further study.

The National Institutes of Health and the National Hemophilia Foundation supported this study.

Note: Contact Kafri at (919) 843-7635 or kafri@med.unc.edu.

School of Medicine contact: Les Lang, (919) 843-9687 or llang@med.unc.edu

Hong Ma, Tal Kafri. A Single-LTR HIV-1 Vector Optimized for Functional Genomics Applications. MOLECULAR THERAPY Vol. 10, No. 1, July 2004

(c) UNC News release

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