Featured Research

from universities, journals, and other organizations

For Different Species, Different Functions For Embryonic MicroRNAs

Date:
May 28, 2009
Source:
Rockefeller University
Summary:
When evolution has lucked into efficient solutions for life's most fundamental problems, it adopts them as invaluable family heirlooms, passing them down as one species evolves into another. So it was reasonable to expect that a key regulator of embryonic development -- a strand of RNA that shepherds stem cells through the process of differentiation -- might play the same role in all vertebrates, from fish to people. New research, however, has shown that when it comes to microRNAs, what works for one animal may not work the same way in another.

Fated embryos. To study the function of a family of microRNAs in early embryonic development, researchers blocked its action in different species, including the African clawed frog. Compared to a normal frog embryo (top), an embryo deprived of the microRNA has major developmental problems.
Credit: Image courtesy of Rockefeller University

When evolution has lucked into efficient solutions for life’s most fundamental problems, it adopts them as invaluable family heirlooms, passing them down as one species evolves into another. So it was reasonable to expect that a key regulator of embryonic development — a strand of RNA that shepherds stem cells through the process of differentiation — might play the same role in all vertebrates, from fish to people. New research, however, has shown that when it comes to microRNAs, what works for one animal may not work the same way in another.

Researchers at The Rockefeller University looked at the role of a family of microRNAs in the African clawed frog embryo and human embryonic stem cells, comparing their findings with earlier ones in fish, and found that although the genes for these microRNAs were identical across the three species, their function was not. “The naοve assumption is that if we understand what these microRNAs do in a fish or in the frog, we can extrapolate to humans,” says Ali H. Brivanlou, head of the Laboratory of Molecular Vertebrate Embryology. “This study shows that this assumption is flawed when it comes to microRNAs.”

Discovered in the 1990s and first named in 2001, microRNAs are single strands of RNA that put the brakes on gene expression, halting the translation process that makes proteins. Postdoctoral associate Alessandro Rosa picked a particular family of these chemical brakes specific to vertebrates and known to operate only in the early stages of embryogenesis, shaping the fates of embryonic stem cells toward the various tissues and organs into which they will grow. The microRNAs Rosa studied regulate what’s known as the Nodal pathway, a process central to initial cell differentiation. The relative proportion of certain activator proteins — called Nodals — and inhibitory proteins — Lefties — determine how active the pathway is. Rosa believed that this particular group of microRNAs disrupts the Lefties, helping to sustain the Nodal pathway, which is central to development. And his research, published last month in Developmental Cell, bore that out.

Using a chemical technique to block the microRNA in frog embryos, Rosa found that the embryos failed to develop the upper, or dorsal, and anterior portions of their growing bodies, including the tissues that would eventually become neurons and eyes. Instead, their ventral part was expanded, forming a belly-like protrusion underneath. Performing the same experiment on human embryonic stem cells, he discovered a slightly different effect: Markers for tissues fated to develop into the nervous system — the neuroectoderm — were up, and markers for the mesendoderm — the precursor of bones, muscles and blood, among other things — were down.

The big difference, the researchers found, was what the microRNAs targeted in each species. Previous experiments had shown that this particular microRNA targets both the Nodals and the Lefties in zebra fish. Rosa found that the same microRNA in both frogs and humans also targets the Lefties. But in humans, the microRNA does not directly target the Nodal protein, and in frogs, it targets only the pathway’s weakest elements.

“Although the microRNAs are evolutionarily conserved, their target changes across species. These are genetic tools that nature has invented, much like the screwdriver, to build different things for different species,” Brivanlou says.


Story Source:

The above story is based on materials provided by Rockefeller University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Rosa et al. The miR-430/427/302 Family Controls Mesendodermal Fate Specification via Species-Specific Target Selection. Developmental Cell, 2009; 16 (4): 517 DOI: 10.1016/j.devcel.2009.02.007

Cite This Page:

Rockefeller University. "For Different Species, Different Functions For Embryonic MicroRNAs." ScienceDaily. ScienceDaily, 28 May 2009. <www.sciencedaily.com/releases/2009/05/090522171001.htm>.
Rockefeller University. (2009, May 28). For Different Species, Different Functions For Embryonic MicroRNAs. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2009/05/090522171001.htm
Rockefeller University. "For Different Species, Different Functions For Embryonic MicroRNAs." ScienceDaily. www.sciencedaily.com/releases/2009/05/090522171001.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Rare Lion Cubs Make Debut at Belgrade Zoo

Raw: Rare Lion Cubs Make Debut at Belgrade Zoo

AP (Oct. 17, 2014) — Two white lion cubs were born in Belgrade zoo three weeks ago. White lions are a rare mutation of a species found in South Africa and some cultures consider them divine. (Oct. 17) Video provided by AP
Powered by NewsLook.com
The Best Foods To Boost Your Mood

The Best Foods To Boost Your Mood

Buzz60 (Oct. 17, 2014) — Feeling down? Reach for the refrigerator, not the medicine cabinet! TC Newman (@PurpleTCNewman) shares some of the best foods to boost your mood. Video provided by Buzz60
Powered by NewsLook.com
Sweet Times for Hard Cider Makers

Sweet Times for Hard Cider Makers

AP (Oct. 16, 2014) — With hard cider making a hardcore comeback across the country, craft makers are trying to keep up with demand and apple growers are tapping a juicy new revenue stream. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Meet Garfi the Angry Cat

Meet Garfi the Angry Cat

Buzz60 (Oct. 16, 2014) — Garfi is one frowny, feisty feline - downright angry! Ko Im (@koimtv) introduces us to the latest animal celebrity taking over the Internet. You can follow more of Garfi's adventures on Twitter (@MeetGarfi) and Facebook (Garfi). Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins