Navigation Links
Root or shoot? EAR calls the shots
Date:2/7/2008

La Jolla, CA Controlled by a tightly regulated choreography that determines what should go up and what should go down, plants develop along a polar axis with a root on one end and a shoot on the other.

While studying why a defective TOPLESS gene causes plant embryos to develop into a seedling topped with a second root instead of a stem with leaves, researchers at the Salk Institute for Biological Studies hit upon the linchpin that ensures that plants are neither all root nor all shoot.

Turns out the question, Root or shoot" literally hinges on the EAR domain, a short protein sequence only six amino acids long.

The Salk researchers findings, published in the February 7 issue of Science Express, explain how mutations in TOPLESS can switch a plant cells fate from shoot to root and in the process clarify the purpose of the so-called EAR motif, a protein domain whose function has puzzled plant scientists for several years.

Weve known for a while that the EAR domain can turn off transcription, but how it did this was an open question, says the studys lead author, Jeffrey A. Long, Ph.D., an assistant professor in the Plant Molecular and Cellular Biology Laboratory. We didnt set out to fish for molecules that bind to the EAR domain, but when we used TOPLESS as a bait, thats what we found.

Scientists and home gardeners alike have been messing with plants basic architecture for years: Permanently switch on a gene called BODENLOS (or bottomless) and plants forgo root development altogether. Dip plant cuttings into hormone rooting powder and roots start to sprout where none have been. The active ingredient, a synthetic version of the plant hormone auxin that regulates root growth in plants, overrides the molecular switch that keeps auxin-responsive genes turned off in parts of the plant that are above ground.

In an earlier study, Long and his team had discovered that the switch is none other than TOPLESS, the protein encoded by the TOPLESS gene. It had become clear that TOPLESS functions as a so-called co-repressor, which regulate gene expression by inhibiting the activity of transcription factors. Transcription factors control gene activity by binding to DNA sequences adjacent to a gene. But exactly how TOPLESS silences genes necessary for root development has remained unclear.

Hoping to gain insight into how TOPLESS functions by looking at the company it keeps, lead author Heidi Szemenyei, a former graduate student in Longs lab and now a postdoctoral researcher at UC Berkeley, searched for interacting partners in the plant Arabidopsis thaliana. This wee weed was the first flowering plant to have its genome unlocked and is loved by plant biologists for its short generation time.

She discovered that BODENLOS, a transcriptional repressor that silences auxin-responsive genes, relies on its EAR domain to recruit the co-repressor TOPLESS to help with the job. While auxins are found throughout the whole plant, BODENLOS is only active in the shoot, ensuring that no accidental roots sprout above ground.

The coupling of TOPLESS to BODENLOS provides an elegant mechanism for the plant to control the activity of auxin-responsive genes, says Long.


'/>"/>
Contact: Gina Kirchweger
kirchweger@salk.edu
858-453-410-01340
Salk Institute
Source:Eurekalert  

Related biology news :

1. Core blimey! University of Leicester scientist calls for geological time machine
2. Analysis calls for medical device information to better serve patients and doctors
3. Island monkeys do not recognize big cat calls
4. UC Davis bird-flu expert calls for changes in early-warning system
5. Rice University expert calls for coordination in nanotechnology research
6. American Chemical Society calls green chemistry bill a smart step
7. bioMETRX, Inc. Calls Series B Warrants
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Root or shoot? EAR calls the shots
(Date:4/14/2016)... BioCatch ™, the global ... the appointment of Eyal Goldwerger as CEO. ... Goldwerger,s leadership appointment comes at a time of significant ... of its platform at several of the world,s largest ... unique cognitive and physiological factors, is a winner of ...
(Date:3/31/2016)... March 31, 2016   ... or the "Company") LegacyXChange is excited to ... its soon to be launched online site for trading ... ) will also provide potential shareholders a sense ... technology to an industry that is notorious for fraud. ...
(Date:3/29/2016)... March 29, 2016 LegacyXChange, Inc. ... "LEGX" and SelectaDNA/CSI Protect are pleased to announce our ... in a variety of writing instruments, ensuring athletes signatures ... created collectibles from athletes on LegacyXChange will be assured ... the DNA. Bill Bollander , CEO ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June, 23, 2016  The Biodesign Challenge (BDC), a ... ways to harness living systems and biotechnology, announced its ... in New York City . ... students, showcased projects at MoMA,s Celeste Bartos Theater during ... , MoMA,s senior curator of architecture and design, and ...
(Date:6/23/2016)... ... , ... In a new case report published today in STEM CELLS Translational ... lymphedema after being treated for breast cancer benefitted from an injection of stem cells ... this debilitating, frequent side effect of cancer treatment. , Lymphedema refers to ...
(Date:6/23/2016)... On Wednesday, June 22, 2016, the ... the Dow Jones Industrial Average edged 0.27% lower to finish ... 0.17%. Stock-Callers.com has initiated coverage on the following equities: Infinity ... NKTR ), Aralez Pharmaceuticals Inc. (NASDAQ: ... ). Learn more about these stocks by accessing their free ...
(Date:6/23/2016)...  Amgen (NASDAQ: AMGN ) today announced ... life sciences incubator to accelerate the development of new ... at QB3@953 was created to help high-potential life science ... early stage organizations - access to laboratory infrastructure. ... two "Amgen Golden Ticket" awards, providing each winner with ...
Breaking Biology Technology: