Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research reveals how cells protect against stress

15.08.2002


Stress happens, and over the eons all species of living things have evolved all sorts of ways to cope. Now, new research has revealed that organisms as diverse as humans and plants share a common set of stress-protection maneuvers that are choreographed by the metabolic machinery in their cells.



The research led by Sarah M. Assmann, the Waller Professor of Plant Biology at Penn State, will be published in the 15 August 2002 issue of the journal Nature.

"We have shown, in more detail than was known before, the chain of cellular events that begins with an environmental stress and ends with an organism’s protective response to that stress," Assmann says. "We also have discovered some previously unknown steps in that process."


Among the team’s discoveries is that one cellular-processing step that originally was discovered in human cells also occurs in plant cells. "A human autoimmune disease and a disorder associated with breast cancer are known to result from a defect in this process, " Assmann says.

Specifically, the Assmann team studied a process triggered in plants by abscisic acid (ABA), a hormone that plants produce when they are stressed by drought. Assmann’s lab discovered two years ago that the ABA hormone activates a type of protein called a kinase, which attaches phosphate groups to other proteins. The resulting cascade of events ultimately causes closure of microscopic pores on the plants’ leaves in an effort to limit the loss of moisture.

In the present research, Assmann’s group found that one of the targets of this ABA-activated kinase is a specific protein that binds RNA. Assmann’s group further discovered that the ABA-induced phosphorylation of the RNA-binding protein caused its association with the RNA encoding dehydrin, a protein known to confer stress-resistance to plant cells.

Scientist have long known that, in both plant and animal cells, proteins designed to do particular jobs are produced from the genetic blueprint contained in the DNA inside the nucleus. In a process known as transcription, nuclear machines first copy the genetic code from the DNA molecules into a "transcribed" RNA molecule and then moves the RNA from the nucleus into the cell’s cytoplasm, where it is "translated" into a protein. But Assmann and other researchers are discovering that RNA-binding proteins mediate a lot of cut-and-paste processing of the newly transcribed "raw" RNA before it is remodeled into "messenger" RNA and allowed to leave the nucleus carrying the blueprint for making a protein.

"A new paradigm that our research suggests is that the ABA hormone regulates the protein complement of a cell not only by controlling the initial transcription process but also by controlling the proteins involved in post-transcriptional remodeling of RNA molecules, including RNAs that encode stress-protective proteins," Assmann explains.

Another of Assmann’s discoveries is that ABA regulates the formation of mysterious islands within the cell’s nucleus called "nuclear speckles." Scientists do not yet know a lot about nuclear speckles in plants, but they do know that nuclear speckles in human cells contain proteins associated with the remodeling of RNA.

By expressing in plant cells the RNA-binding protein with a green fluorescent tag attached, Assmann’s group was able to observe the localization of this protein within the living cell. As she watched through the microscope Assmann observed, for the first time, that ABA induced the relocation of the RNA-binding protein within the nucleus. Upon treatment of the plant tissue with ABA, the fluorescently-tagged RNA-binding proteins quickly gathered together into nuclear speckles that looked like green-glowing islands inside the cell’s nucleus. "To our knowledge, such hormonally induced aggregation of RNA-remodeling proteins into nuclear speckles has not previously been observed either in plant or in animal cells," Assmann says.

In addition to giving researchers these and other important details about the processes that produce protective proteins, Assmann’s research also eventually could give farmers more control over the moisture content of their crops." Our research points to a gene-regulation process that, if turned off after a crop matures, would assure that the pores on a plant’s leaves would stay open, allowing it to dry more quickly in the field," Assmann explains. "In a crop like feed corn, for example, such control would be economically beneficial to farmers, who get a better price for their crop if it has reached its optimal moisture content."


In addition to Assmann, other members of the research team include Jiaxu Li, lead postdoctoral associate, postdoctoral associates Sona Pandey and Carl K.-Y. Ng, Ken-ichiro-Shimazaki and Toshinori Kinoshita at Kyushu University (Japan), and Steven P. Gygi of Harvard Medical School.

This research was supported by the National Science Foundation. Photos: high resolution images for publication are available to reporters from a link at http://www.science.psu.edu/alert/Assmann8-2002.htm

Additional Contact Information:
Sarah M. Assmann: phone 814-863-9579, email sma3@psu.edu

Barbara K. Kennedy | EurekAlert!

More articles from Life Sciences:

nachricht Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg

nachricht Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>