My research studies a molecule called microRNA. Don’t feel bad if you’ve never heard of it, since microRNA is a fairly new discovery. The first microRNA was discovered in 1993, and the second one wasn’t discovered until 2000. We’ve discovered thousands of microRNAs by now, but they’re still not something all biologists are familiar with, let alone non-biologists. I know when my advisor initially suggested I study microRNAs, the first thing I had to do was go read the Wikipedia article. I knew nothing!
So what the heck is a microRNA? As the name implies, it’s a very short RNA found in plants and animals. Its function is a little more complicated, so let’s back up a bit. Most people have heard of the “Central Dogma” from their high school biology courses: DNA is transcribed into messenger RNA, which is then made into protein.
DNA serves as the “blueprint” for how to make an organism.The messenger RNA, which as the name suggests, serves as an intermediate messenger between the blueprints in the nucleus of a cell and the machinery out in the cyotplasm. Once in the cytoplasm, the messenger RNA is read by a ribosome, which produces a protein based on the instructions originally encoded by the DNA.
Messenger RNA can be made in varying quantities, and more messenger RNA leads to more proteins being made. The amount of proteins made is just as important as the type of protein being made. Genes are “off” if no protein is produced, and varying quantities of a protein can have profound effects on how an organism functions. This is why large chromosomal duplications are generally lethal or have major effects (like Down Syndrome) – with an extra chromosome contributing to protein production, protein levels are totally out of whack.
But the Central Dogma isn’t so dogmatic. This is where microRNA comes in. In animals, micoRNA functions as part of a protein complex called the RNA-induced Silencing Complex (RiSC). MicroRNA guides RiSC to a particular messenger RNA through complementary basepairing – the A in microRNA matches with a U in messenger RNA, the G with a C, etc. RiSC will then block from becoming a protein. RiSC can do this by directly degrading the messenger RNA, de-adenylating the messenger RNA’s poly-A tail to lead to degradation, or by recruiting other proteins to get in the way of translation into a protein. So when microRNA targets a messenger RNA, it results in that messenger RNA producing fewer proteins than usual. If enough microRNA is made, it may turn the gene off completely.
MicroRNA is especially important because one microRNA can have dozens to hundreds of messenger RNA targets. This means a single type of microRNA can have really profound effects on an organism. It’s one of the most important regulators of gene expression, and is involved in key biological processes like the differentiation of stem cells into specialized adult cells, cell proliferation, metabolism, and apoptosis (programmed cell death). Because it’s so important, most microRNAs are highly conserved across animals. This is also why microRNA has been heavily implicated in cancer – one small tweak can have drastic effects.
Stay tuned for more riveting information about microRNA evolution later!
This is post 6 of 49 of Blogathon. Donate to the Secular Student Alliance here.
9 comments
Nobby says:
Jun 16, 2012
Shouldn’t it be A to U? Or does microRNA work slightly differently in that regard? I’d be rather surprised to learn that, but I’m one of those that doesn’t work/know much about microRNA, just mRNA.
Jen says:
Jun 16, 2012
You’re correct, I’m just tired and made a mistake in my Blogathon haste :)
Nobby says:
Jun 16, 2012
Ah, okay. Well, considering how awesome all this work is, I think i can forgive you this small mistake. :-p
jstatham027 says:
Jul 22, 2018
Keep doing awesome read few posts on this site and i consider that your web journal is exceptionally fascinating and has sets of fabulous data. Web Design and Development
jstatham027 says:
Jan 14, 2019
Some really helpful information in there. Why not hold some sort of contest for your readers? company registration
jstatham027 says:
Feb 20, 2019
I am extremely impressed together with your writing abilities neatly as with the structure for your weblog. Is this a paid subject matter or did you modify it yourself? Anyway stay up the nice high quality writing, it’s rare to peer a nice blog like this one nowadays. nursery in Dubai
jstatham027 says:
Feb 20, 2019
You actually make it seem so easy with your presentation but I find this topic to be actually something that I think I would never understand. It seems too complicated and extremely broad for me. I’m looking forward for your next post, I’ll try to get the hang of it! affiliate marketing keyword research
jstatham027 says:
Feb 20, 2019
I don’t normally check out these types of sites (I’m a pretty modest person) – but even though I was a bit shocked as I was reading, I was definitely a bit excited as well. Thanks for making my day sidewalk snow clearing
jstatham027 says:
Feb 26, 2019
angelina produced that checklist? that dress is awful. not just is it boring but it makes her appear like she”s trying to cover up the truth that she looks emaciated. her shoulders are so bony it looks like she left the hanger in it. she normally looks wonderful. pretpark Bobbejaanland overnachten