As a follow up to yesterday’s discussion on metal ions and nucleic acid binding proteins, I wanted to share a scientific story in which I was not directly involved, but did get to see relatively close up.
Because of my interests, I attended many scientific meetings on the topic of metal control of gene expression. One of the most important and well-studied systems involved iron control of gene expression.
Iron is a dangerous element. It is essential for many proteins such as hemoglobin, cytochromes and iron-sulfur proteins, but unconstrained iron can promote damaging free radical reactions. Because of this, organisms including human beings having elaborate systems for iron storage and transport.
For example, almost all organisms encode ferritin, a protein that can form beautiful protein shells that can store large amounts of iron inside them. A 24-subunit ferritin shell can store approximately 4500 iron ions.
The expression of the ferritin gene is regulated at the level of RNA. Ferritin mRNA has a structure in the 5’-untranslated region (called an Iron Responsive Element or IRE) that is bound by a protein by under conditions of low iron. This blocks translation so no ferritin is produced.
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https://en.wikipedia.org/wiki/Ferritin
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