OAK RIDGE, Tenn., Jan. 15, 1997 --Imagine looking down at a yellow carpet and seeing a long, brown, sinuous thread with an occasional knot. That's the picture scientists at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) get on a computer screen when using an atomic force microscope (AFM) to image a serpentine strand of DNA.
And when they get the picture, they get excited about the "knots." The reason: each knot is really a "protein bump" formed when a protein recognizes and attaches to a specific site on a DNA molecule.
These ORNL scientists are developing this new imaging approach as an alternative technology for DNA mapping. They think their technique will be more accurate and perhaps faster than conventional methods.
DNA, sometimes referred to as the blueprint for life, is a nucleic acid that carries the genetic information in the cell. It consists of two long chains of deoxyribose sugar molecules hooked together by phosphate groups and twisted into a double helix, not unlike a spiral staircase.
The work was done by Dave Allison and Mitch Doktycz, both of ORNL's Molecular Imaging Group, which is headed by Bruce Warmack. The group is in the Health Sciences Research Division.
The AFM is a microscope capable of atomic resolution that produces a three-dimensional image by tracing the surface of a material, similar to the arm and needle of a phonograph playing a record.
The research, which was performed for the Human Genome Project, was funded by the Department of Energy's Office of Health and Environmental Research. Continued research on the binding of transcription factors is being supported by ORNL's Laboratory Directed Research and Development Program.
ORNL, one of the Department of Energy's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Research Corp.