Biochemical controls: making insulin (Introduction)

by David Turell , Tuesday, July 25, 2023, 18:02 (278 days ago) @ David Turell

A study in flies:

https://www.sciencedaily.com/releases/2023/07/230724122634.htm

"Studying insulin production in humans or mammals is difficult. In humans, the pancreas is situated behind the liver. It doesn't regenerate well, and it can't be sampled in live subjects. But in flies, their insulin cells are actually in their brains, function like neurons, and are physically accessible to researchers. In fruit flies, the researchers looked at a tag called RNA N-6 adenosine methylation, or m6A.

"To study the m6A tag, the researchers first identified the RNAs that have the tag. Then they labeled insulin cells with a fluorescent molecule, and used confocal microscopy to visualize how much insulin is produced by the insulin cell. They did this under two conditions: first, they knocked out the m6A enzyme, responsible for decorating the mRNA with m6A tags, in insulin cells. Second, they removed the m6A tags by using CRISPR, a technology used to edit DNA, to mutate the modified As.

In both cases, the flies' ability to produce insulin was greatly reduced.

"'We found that this photocopy of the DNA for insulin, this mRNA, had a specific tag that, when it is present, a ton of the insulin hormone is made," said Dus, associate professor of molecular, cellular and developmental biology. "But without the signal, flies had much less insulin and developed hallmarks of diabetes."

"This chemical tag is conserved -- or unchanged -- in fish, mice and humans.

"'So it's likely that insulin production is also regulated through this kind of mechanism in humans," Wilinski said. "There is an obesity and diabetes epidemic not just in the United States, but across the world. Our finding is another bit of evidence about how this disease happens."

"Dus says the discovery fleshes out the understanding of the biology of insulin and the physiology of diseases of energy homeostasis. Low levels of chemical tags have been observed in people with Type 2 diabetes. Restoring the levels of these tags may also help with combating diabetes and metabolic disease, she says."

Comment: every process in living cells depends upon specific biochemicals. We can identify them but we still do not know how the molecule achieves its purpose. Sucj specificity is not possible with any form of chance evolution.