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Nobel Prize in Physiology and Medicine: micro RNA

What does it mean? Science is a process. We learn as we research, and life is complicated.

When I started college in 1966, it wasn’t even clear to me how many chromosomes there were in a human cell. Maybe it was because old textbooks still circulated with the old number, 48. Actually, Joe Hin Tjio and Albert Levan reported in 1956 that the correct human chromosome number was 46, not 48, as was supposedly established some three decades earlier. Textbooks are full of errors.

Gene regulation determines differences between types of cells, and if it goes off track, it can lead to diseases such as cancer, diabetes, or autoimmunity. Researchers now know that the human genome provides instructions for over 1,000 forms of microRNA, which are essential to the development and function of organisms. Thank you, Victor Ambros and Gary Ruvkun, winners of this year’s Nobel Prize for Physiology and Medicine. They started at the lab of H. Robert Horvitz, another Nobel Prize winner (2002 for his studies on cell death).

MicroRNAs (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. They are found in plants, animals, and some viruses. MicroRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression.

In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. What do they do? miRNAs base-pair to complementary sequences in mRNA molecules and then “silence” those mRNA molecules by one (or more) of the following processes:

1) Cleaving the mRNA strand into two pieces
2) Destabilizing the mRNA by shortening its poly(A) tail
3) Decreasing translation of the mRNA into protein

 

Figure: How microRNA regulates cell metabolism. Kelvinsong  –  https://commons.wikimedia.org/w/index.php?curid=23311105

 

What’s the take-home message? We shouldn’t play with what we don’t know.

When “investors” are attracted to a new toy, beware—especially investors with enough money to damage society by funding “bad science.” With Theranos, they “just” lost money, and maybe they killed a few patients who trusted their health to Theranos. But lousy science has the potential to be catastrophic. How? We can hurt the ecosystem when we don’t know what we are doing.

Remember: with great (scientific) power comes great responsibility.

 

Hannah

 

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