Featured Research

from universities, journals, and other organizations

Glimpses Of Earliest Forms Of Life On Earth: Remnant Of Ancient 'RNA World' Discovered

Date:
July 18, 2008
Source:
Yale University
Summary:
Some bacterial cells can swim, morph into new forms and even become dangerously virulent -- all without initial involvement of DNA. Researchers describe how bacteria accomplish this amazing feat in the journal Science -- and in doing so provide a glimpse of what the earliest forms of life on Earth may have looked like.

Ronald Breaker and the chemical structure of cyclic di-GMP.
Credit: Image courtesy of Yale University

Some bacterial cells can swim, morph into new forms and even become dangerously virulent - all without initial involvement of DNA. Yale University researchers describe July 18 in the journal Science how bacteria accomplish this amazing feat - and in doing so provide a glimpse of what the earliest forms of life on Earth may have looked like.

To initiate many important functions, bacteria sometimes depend entirely upon ancient forms of RNA, once viewed simply as the chemical intermediary between DNA's instruction manual and the creation of proteins, said Ronald Breaker , the Henry Ford II Professor of Molecular, Cellular and Developmental Biology at Yale and senior author of the study.

Proteins carry out almost all of life's cellular functions today, but many scientists like Breaker believe this was not always the case and have found many examples in which RNA plays a surprisingly large role in regulating cellular activity. The Science study illustrates that - in bacteria, at least - proteins are not always necessary to spur a host of fundamental cellular changes, a process Breaker believes was common on Earth some 4 billion years ago, well before DNA existed.

"How could RNA trigger changes in ancient cells without all the proteins present in modern cells? Well, in this case, no proteins, no problem," said Breaker, who is also a Howard Hughes Medical Institute investigator.

Breaker's lab solved a decades-old mystery by describing how tiny circular RNA molecules called cyclic di-GMP are able to turn genes on and off. This process determines whether the bacterium swims or stays stationary, and whether it remains solitary or joins with other bacteria to form organic masses called biofilms. For example, in Vibrio cholerae, the bacterium that causes cholera, cyclic di-GMP turns off production of a protein the bacterium needs to attach to human intestines.

The tiny RNA molecule, comprised of only two nucleotides, activates a larger RNA structure called a riboswitch. Breaker's lab discovered riboswitches in bacteria six years ago and has since shown that they can regulate a surprising amount of biological activity. Riboswitches, located within single strands of messenger RNA that transmit a copy of DNA's genetic instructions, can independently "decide'' which genes in the cell to activate, an ability once thought to rest exclusively with proteins.

Breaker had chemically created riboswitches in his own lab and - given their efficiency at regulating gene expressions - predicted such RNA structures would be found in nature. Since 2002, almost 20 classes of riboswitches, including the one described in today's paper, have been discovered, mostly hidden in non-gene-coding regions on DNA.

"We predicted that there would be an ancient 'RNA city' out there in the jungle, and we went out and found it,'' Breaker said.

Bacterial use of RNA to trigger major changes without the involvement of proteins resolves one of the questions about the origin of life: If proteins are needed to carry out life's functions and DNA is needed to make proteins, how did DNA arise?

The answer is what Breaker and other researchers call the RNA World. They believe that billions of years ago, single strands of nucleotides that comprise RNA were the first forms of life and carried out some of the complicated cellular functions now done by proteins. The riboswitches are highly conserved in bacteria, illustrating their importance and ancient ancestry, Breaker said.

Understanding how these RNA mechanisms work could lead to medical treatments as well, Breaker noted. For instance, a molecule that mimics cyclic di-GMP could be used to disable or disarm bacterial infections such as cholera, he said.


Story Source:

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


Cite This Page:

Yale University. "Glimpses Of Earliest Forms Of Life On Earth: Remnant Of Ancient 'RNA World' Discovered." ScienceDaily. ScienceDaily, 18 July 2008. <www.sciencedaily.com/releases/2008/07/080717140459.htm>.
Yale University. (2008, July 18). Glimpses Of Earliest Forms Of Life On Earth: Remnant Of Ancient 'RNA World' Discovered. ScienceDaily. Retrieved October 2, 2014 from www.sciencedaily.com/releases/2008/07/080717140459.htm
Yale University. "Glimpses Of Earliest Forms Of Life On Earth: Remnant Of Ancient 'RNA World' Discovered." ScienceDaily. www.sciencedaily.com/releases/2008/07/080717140459.htm (accessed October 2, 2014).

Share This



More Fossils & Ruins News

Thursday, October 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Battle of New Orleans Cannon Gets New Carriage

Battle of New Orleans Cannon Gets New Carriage

AP (Sep. 30, 2014) A Spanish cannon used in the Battle of New Orleans and weighing nearly 3 tons was lowered Tuesday by pulleys, chains and muscle onto a new gun carriage like one that might have held it once aboard a navy ship. (Sept. 30) Video provided by AP
Powered by NewsLook.com
2,000 Year Old Pre-Inca Cloak on Display in Lima

2,000 Year Old Pre-Inca Cloak on Display in Lima

AFP (Sep. 27, 2014) A 2,000 year-old Pre-Inca cloak that is believed to represent an agricultural calendar of the Paracas culture is on display in Lima. Duration: 00:39 Video provided by AFP
Powered by NewsLook.com
Original Mozart Sonata Manuscript Found in Budapest

Original Mozart Sonata Manuscript Found in Budapest

AFP (Sep. 26, 2014) Considered lost for over two centuries, the original manuscript of one of the most famous works of Mozart's Sonata in A major has been uncovered in a library in Budapest. Duration: 01:04 Video provided by AFP
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