Two scientists in the University of Massachusetts Amherst’s Chemistry Department have discovered how DNA and RNA form a stable enough structure to allow for transcription, the process where information stored in DNA is copied out to RNA, according to a recent press release.

The discovery by the chemists, Professor Craig Martin and graduate student Xiaoqing Liu, was found during a preliminary phase of transcription, called elongation. During this phase, the DNA strand opens up and a molecule called RNA polymerase forms a loop around both the DNA strand and the RNA strand that the information is being copied to. According to the release, this process had been previously thought of incorrectly in two-dimensional terms. It was believed that the RNA polymerase inserted itself between RNA and DNA, where in reality, in a three-dimensional model, the RNA wraps around these two strands.

Transcription, a vital step in the life of the cell, occurs in several different ways. When the DNA is transcribed into RNA codes for a protein, the RNA is called messenger RNA. DNA can also code for ribosomal RNA and transfer RNA.

DNA, deoxynucleic acid, is a double helix-shaped molecule that stores genetic information in cells. Its primary components are thymine, adenine, guanine and cytosine. RNA, which stands for ribonucleic acid, is involved in making use of the information stored in the DNA, especially for manufacturing proteins. It has all the same molecules as DNA, except that thymine is replaced with uracil.  

Martin and Liu call the structure a topological lock. According to the press release, the topological lock concept helps to explain two key features that had been mysteries to scientists before. One mystery is why most transcription processes involve eight base pairs. The release explains that the topological lock model has determined eight to be the most efficient number for accurate transcriptions. The model also explains how the “transcription bubble” that forms when all the various molecules are doing their jobs remains stable instead of breaking apart and scattering their pieces.

Their findings have appeared in the Journal of Biological Chemistry and the two chemists will continue their research. Martin will focus on RNA polymerase and RNA synthesis.

Matthew M. Robare writes for the Collegian. He can be reached at [email protected].