Genome complexity: primordial enhancers (Introduction)

by David Turell , Wednesday, November 23, 2022, 00:27 (731 days ago) @ David Turell

In a heat cell response from the very first cells:

https://phys.org/news/2022-11-primordial-super-enhancers-early-snapshot-mechanisms.html

"Transcriptional condensates are membrane-less compartments—almost like organelles, but lacking a membrane—within the nucleus of the cell that bring together and concentrate transcriptional machinery to allow for the rapid and high-level transcription of specific critical genes under certain conditions, such as to specify a cell lineage or in response to stress.

"In response to high environmental temperatures, cells turn on molecular chaperones, which act to help maintain protein stability. This heat shock response can be hijacked by cancer cells to help mutated proteins stay folded, and it gets broken down in neurodegenerative diseases such as Alzheimer's disease, where a lack of molecular chaperones leads to excessive protein aggregation.

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"Previous research in mammalian cells had shown that eukaryotes use these membrane-less compartments to drive high-level gene expression by creating hubs where relevant DNA sequences and transcriptional activators can collect and drive transcription. In the current study, the researchers used a series of genetic mutations to demonstrate that yeast cells use the same mechanism to coordinate the heat shock response.

"'In our prior research, we saw that the genes being regulated in response to heat stress coalesce in 3D space to be activated," said Surabhi Chowdhary, a postdoctoral scholar in the Pincus lab at UChicago. "This study provides evidence that these genes are driven together in 3D space by these biomechanical condensates to facilitate gene transcription."

"This is the first time these condensates have been seen in a non-eukaryotic species, demonstrating that these structures are very ancient, dating back to a very early common ancestor and conserved across species. "This means that cells have been doing this high-level gene expression for a billion years," said Pincus. "And when these condensates form, they're not forming at an individual gene, but instead have the capacity to bring a bunch of genes together to activate them all at the same time."

Comment: the fact that this mechanism existed at the start of life strongly support design theory in that it is a design prepared for future use. A wise designer will set the process up this way.