Conversation

Yay! Victor Ambros and Gary Ruvkun won the Nobel for the discovery of microRNA and its role in post-transcriptional gene regulation!

Wait - wut? What's microRNA? 🤔 Time to hit the books.

Okay, so as we know, the information in short stretches of DNA get copied to short pieces of RNA called messenger RNA or 'mRNA'. This is called 'transcription'. It's a step in how genes get expressed as proteins.

But sometimes these short pieces of RNA bend over and stick to themselves, forming 'hairpin RNA'. You see one at the top of this picture, where it's called 'pre-microRNA'.

Then sometimes these hairpins get cut in half, forming micro-RNAs. And these attach themselves to other RNAs that are trying to code for proteins! This 𝑝𝑟𝑒𝑣𝑒𝑛𝑡𝑠 those RNAs from doing their job. So it's a way of 𝑟𝑒𝑔𝑢𝑙𝑎𝑡𝑖𝑛𝑔 the expression of genes.

There are various ways a micro-RNA actually messes up the mRNA it's attached to. In humans, apparently, they make the 'tail' of the mRNA degrade faster than it would usually.

But now I want to know how the cell 'knows' it should produce micro-RNAs of a certain sort, to prevent some gene from being expressed.

Like everything in biology, this is going to be complicated. I read that a single micro-RNA may stick to hundreds of different mRNAs. It would be cool if a single micro-RNA prevents the expression of a bunch of 𝑟𝑒𝑙𝑎𝑡𝑒𝑑 genes: genes that a liver cell needs, for example, but not a lung cell. Then the micro-RNA trick could be a powerful high-level way to affect cell development.

https://en.wikipedia.org/wiki/MicroRNA