At last, a close-up view of the transcription process

In a discovery that offers insights into fundamental cellular processes, Yale researchers have observed for the first time the transcription of genetic information from a DNA template to viral RNA. “In general,” says Thomas A. Steitz, Ph.D., professor of molecular biophysics and biochemistry, “the initiation of transcription of DNA into RNA is one of the most heavily regulated steps in cells. It is what makes one cell different from another.” Steitz called the initiation events, observed through X-ray crystallography, “scrunching.” The DNA, he said, coils like a rope inside the enzyme polymerase, accumulating in the enzyme’s active site as the first short RNA transcript is being synthesized. The findings were published in the journal Science on Dec. 17.