Genome complexity: 3-D DNA football controls (Introduction)

by David Turell , Wednesday, September 27, 2017, 14:56 (2396 days ago) @ David Turell

Very sophisticated molecular techniques have found controlling 'footballs' of transcription factors that fit in tightly packed DNA to speed reaction times:

https://phys.org/news/2017-09-scientists-genes-nano-footballs.html

"Crucially, they discovered that transcription factors operate not as single molecules as was previously thought, but as a spherical football-like cluster of around seven to ten molecules of roughly 30 nanometres in diameter.

***

"'We had no idea that we would discover that transcription factors operated in this clustered way. The textbooks all suggested that single molecules were used to switch genes on and off, not these crazy nano footballs that we observed."

"The team believe the clustering process is due to an ingenious strategy of the cell to allow transcription factors to reach their target genes as quickly as possible.

"Professor Leake said: "We found out that the size of these nano footballs is a remarkably close match to the gaps between DNA when it is scrunched up inside a cell. As the DNA inside a nucleus is really squeezed in, you get little gaps between separate strands of DNA which are like the mesh in a fishing net. The size of this mesh is really close to the size of the nano footballs we see.

"'This means that nano footballs can roll along segments of DNA but then hop to another nearby segment. This allows the nano football to find the specific gene it controls much more quickly than if no nano hopping was possible. In other words, cells can respond as quickly as possible to signals from the outside, which is an enormous advantage in the fight for survival.'"

Comment: Life's processes run at very high speed. This 3-D arrangement is logical planning to help get that speed. This must be designed from the beginning of life, or we must assume life ran very slowly at the start.