Featured Research

from universities, journals, and other organizations

New understandings of circadian rhythms

Date:
July 13, 2011
Source:
NIH/National Institute of General Medical Sciences
Summary:
A tiny plant called Arabidopsis thaliana just helped scientists unearth new clues about the daily cycles of many organisms, including humans.

Soybeans grow in spurts just before dawn.
Credit: UC San Diego

A tiny plant called Arabidopsis thaliana just helped scientists unearth new clues about the daily cycles of many organisms, including humans. This is the latest in a long line of research, much of it supported by the National Institutes of Health, that uses plants to solve puzzles in human health.

While other model organisms may seem to have more in common with us, greens like Arabidopsis provide an important view into genetics, cell division and especially light sensing, which drives 24-hour behavioral cycles called circadian rhythms.

Some human cells, including cancer cells, divide with a 24-hour rhythm. One of the main human circadian rhythm genes, cryptochrome, has been associated with diabetes and depression. Both of these discoveries grew from work with plants.

"We don't have stems and we don't flower, but our body parts, like those of plants, are controlled by circadian clocks," says NIH geneticist Laurie Tompkins. "Clocks operate more or less the same way in all organisms, but some aspects of clock function are easier to study in plants."

The new work, released this week in the early online publication of Nature, investigated why Arabidopsis does its major stem-growing in the dark -- a pattern common to most plants. Biologist Steve Kay and colleagues at the University of California, San Diego, report that a specific trio of proteins regulates the rhythm in Arabidopsis stems.

The group of proteins, called the evening complex, interacts in the early evening to silence two genes that usually promote plant growth. When the evening complex's activity trails off a few hours before dawn, proteins release the brakes on growth and plants enter their nightly phase of rapid stem elongation.

When Kay's team mutated the three genes that code for the evening complex, they noticed that this made the Arabidopsis biological clock run out of sync -- stems grew unusually long and flowered early.

Scientists aren't yet certain why night is the best time for stems to grow, but Kay speculates it has to do with using resources efficiently. Plants pick up carbon and nitrogen during the day, then store these essential nutrients as starch and proteins. "In the later night, they can release these resources in a coordinated fashion to provide the building blocks for stem growth," says Kay.

"Our understanding of human health and the role of clocks in health and disease can greatly benefit from studying how clocks work in plants," he adds.

Kay's work could also shed light on how clock genes regulate cell division in human embryos.

From Crops to Cures

Scientists like Kay are interested in answering basic biological questions, but others who work with plants have their eyes on future disease therapies.

Plant-based molecules, for instance, are being used to target reservoirs of HIV that hide out in their hosts. At the University of California, Berkeley, chemist Jay Keasling is looking for simple ways to get microbes to produce greater quantities of these plant-based molecules at lower cost.

How plants like Arabidopsis suppress harmful genes may also help improve HIV therapies. A team of biologists led by Craig Pikaard at Washington University in St. Louis is investigating RNA polymerases, chemicals important in determining which genes get switched on, to learn how plants silence harmful virus-derived genes. Similar silencing pathways could be harnessed for HIV therapies.

More generally, scientists are looking toward plants as a medicinal source. Chemist Sarah O'Connor at MIT is genetically engineering periwinkle plants, the natural source of the anticancer drug vinblastine, to produce variations of the drug with halogens attached. Halogens make some medicines last longer in the body, meaning that probing periwinkle's capabilities could make cancer treatments more effective.


Story Source:

The above story is based on materials provided by NIH/National Institute of General Medical Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Dmitri A. Nusinow, Anne Helfer, Elizabeth E. Hamilton, Jasmine J. King, Takato Imaizumi, Thomas F. Schultz, Eva M. Farrι, Steve A. Kay. The ELF4–ELF3–LUX complex links the circadian clock to diurnal control of hypocotyl growth. Nature, 2011; DOI: 10.1038/nature10182

Cite This Page:

NIH/National Institute of General Medical Sciences. "New understandings of circadian rhythms." ScienceDaily. ScienceDaily, 13 July 2011. <www.sciencedaily.com/releases/2011/07/110713131642.htm>.
NIH/National Institute of General Medical Sciences. (2011, July 13). New understandings of circadian rhythms. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2011/07/110713131642.htm
NIH/National Institute of General Medical Sciences. "New understandings of circadian rhythms." ScienceDaily. www.sciencedaily.com/releases/2011/07/110713131642.htm (accessed September 22, 2014).

Share This



More Plants & Animals News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) — The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
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:

More Coverage


Biologists Discover an 'evening' Protein Complex That Regulates Plant Growth

July 13, 2011 — Farmers and other astute observers of nature have long known that crops like corn and sorghum grow taller at night. But the biochemical mechanisms that control this nightly stem elongation, common to ... read more
from the past week

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