The human body's roughly 30 trillion cells don't need all of their genes switched on at once. Instead, cells tightly control the activity of their genes — and recently, scientists uncovered a previously unknown way they accomplish that feat.
Discovered in 1997, backtracking is a process in which RNA polymerase, instead of moving forward along the DNA as it reads a gene, shifts back and pauses. This halt then resolves and the enzyme can move ahead again, churning out RNA."In early days, people thought that once RNA polymerase begins transcription, it will finish it without any problems," Evgeny Nudler, a professor of biochemistry at NYU Langone Health, told Live Science.
By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over.However, sometimes, the polymerase moves back a longer distance, and the extruded RNA blocks the site where those chopping enzymes usually snip. With this roadblock in place, the polymerase stays stuck in its backtracked state for longer periods, instead of just pausing for a short while.
"For the first time, we systematically mapped backtracked events," Nudler told Live Science."And not just any backtracking events, but those which were extensive, where polymerase backtracks for long distances, gets stuck for a long time."While the team expected to find backtracked events, they did not anticipate how prevalent they would be. They observed backtracking in many genes involved in making proteins from RNA; regulating cell division; and copying and packaging DNA.