Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print UCR scientists identify stem-cell genes that help form plant organs

UCR scientists identify stem-cell genes that help form plant organs

February 25, 2009

RIVERSIDE, Calif. - Plant stem-cells are master cells located at the tip of the stem and are part of a structure called the shoot apical meristem (SAM). Here, the stem cells-all clumped together-divide throughout the life of the plant to give rise to other cells, resulting in the formation of above-ground organs such as leaves, flowers, branches and stem.

But despite the important role the stem cells play in plant development, their molecular composition has eluded researchers for long.




Now, working on Arabidopsis, a mustard-like plant that is a model for studying plant biology, a team of researchers at UC Riverside has identified all the genes expressed in the plant's stem cells.

The researchers also identified all the genes expressed in two other SAM cells: niche cells (which are located just beneath the stem cells and which provide signals that regulate the stem cells), and differentiating cells (which are generated by, and surround, the stem cells).

The final product of the researchers' work is a genome-scale, expression map of SAM-an achievement that paves the way to developing better varieties of crops and plants.

Besides revealing the molecular pathways that stem cells employ, the discovery also can help scientists better understand why stem cells-in both plants and animals-give rise to specialized cells at all.

Study results appear online this week in the early edition of the Proceedings of the National Academy of Sciences.

"Our study is the first to reveal the stem-cell signatures for any plant and the first to provide a global view of which genes are expressed, and where, within the SAM," said G. Venugopala Reddy, the lead author of the study and an assistant professor of plant cell biology in the Department of Botany and Plant Sciences. "Since SAM stem-cells are responsible for forming plant organs and determining plant architecture, further analysis of their genes may provide a handle in altering growth rates and growth patterns in economically important crop-species in order to maximize yield."

Reddy stressed that understanding the function and regulation of stem-cell-specific genes is critical to gaining insights into basic questions such as what constitutes stem-cell identity (the ability of cells to remain unspecialized) and what makes them differentiate into specialized cells.

"A comparative analysis of stem-cell-specific genes between plant and animal systems may also lead to a better understanding of stem-cell identity, a concept common to both the systems," he said.

The study breaks ground also in the way Reddy's research team pinned down the stem-cell genes in Arabidopsis.

His lab initially labeled the three different SAM cell types-stem cells, niche cells and differentiating cells-by using different fluorescent proteins. Next, the researchers isolated the three discrete cell populations by first stripping the cell walls to release the cells as free populations. Then, using an instrument called Fluorescence Activated Cell Sorter, they separated each set of cells from the rest of the cell populations.

"Plant biologists have found it difficult to isolate the approximately 35 stem cells in the Arabidopsis shoot system for two main reasons: this is an extremely low number of stem cells and this clump of cells is tightly packed with a waxy coating covering its outer layer," Reddy said. "To meet this challenge, we used specific mutants of Arabidopsis that make more SAMs per plant. In the lab, we also formulated specific combinations of enzymes that efficiently digest away the cell walls."

Reddy explained that the gene expression map his team generated can help researchers track how genes give rise to complex tissues. It also will allow researchers to determine the expression patterns of SAM genes by a mere click of a button on a computer.

"Development of an organ such as SAM is a complex process in which cells constantly exchange information through regulated gene activities," he said. "What we have done so far is to find out which genes are expressed and where. One of the future challenges is to represent the gene expression on actual templates of plant cells, which would generate a dynamic atlas of stem-cell development. Such an atlas can be used to explore how genes function as a network to bring about stem-cell function."

Reddy acknowledged that developing the atlas is a difficult venture, requiring a synthesis of multiple disciplines such as genomics, live-imaging and informatics sciences.

"But our work breaks ground to make this a reality and we have already initiated some work in this direction," he said.

University of California - Riverside



Related Stem Cells Current Events and Stem Cells News Articles Stem Cells Current Events and Stem Cells News RSS Stem Cells Current Events and Stem Cells News RSS
First use of antibody and stem cell transplantation to successfully treat advanced leukemia
For the first time, researchers at Fred Hutchinson Cancer Research Center have reported the use of a radiolabeled antibody to deliver targeted doses of radiation, followed by a stem cell transplant, to successfully treat a group of leukemia and pre-leukemia patients for whom there previously had been no other curative treatment options.

Magnetic nanoparticles to simultaneously diagnose, monitor and treat
Whether it's magnetic nanoparticles (mNPs) giving an army of 'therapeutically armed' white blood cells direction to invade a deadly tumour's territory, or the use of mNPs to target specific nerve channels and induce nerve-led behaviour (such as the life-dependant thumping of our hearts), mNPs have come a long way in the past decade.

Of mice and men: Stem cells and ethical uncertainties
The recent creation of live mice from induced pluripotent stem cells (iPSCs) not only represents a remarkable scientific achievement, but also raises important issues, according to bioethicists at The Johns Hopkins University's Berman Institute of Bioethics.

NIH-funded researchers transform embryonic stem cells into human germ cells
Researchers funded in part by the National Institutes of Health have discovered how to transform human embryonic stem cells into germ cells, the embryonic cells that ultimately give rise to sperm and eggs.

Stem cell therapy may offer hope for acute lung injury
Researchers at the University of Illinois at Chicago College of Medicine have shown that adult stem cells from bone marrow can prevent acute lung injury in a mouse model of the disease.

Placental precursor stem cells require testosterone-free environment to survive
Trophoblast stem cells (TSCs), cells found in the layer of peripheral embryonic stem cells from which the placenta is formed, are thought to exhibit "immune privilege" that aids cell survivability and is potentially beneficial for cell and gene therapies.

Endocrine Society calls for expanded scope and funding for stem cell research
Stem cell research holds great promise for the treatment of millions of Americans with debilitating and possibly fatal diseases.

Experimental treatments restore partial vision to blind people
Two experimental treatments, a retinal prosthesis and fetal tissue transplant, restored some vision to people with blinding eye diseases. The findings, presented at Neuroscience 2009, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news on brain science and health, may lead to new treatments for the blind.

Scientists demonstrate link between genetic defect and brain changes in schizophrenia
Researchers at the University of North Carolina at Chapel Hill School of Medicine have found that the 22q11 gene deletion - a mutation that confers the highest known genetic risk for schizophrenia - is associated with changes in the development of the brain that ultimately affect how its circuit elements are assembled.

Small mechanical forces have big impact on embryonic stem cells
Applying a small mechanical force to embryonic stem cells could be a new way of coaxing them into a specific direction of differentiation, researchers at the University of Illinois report. Applications for force-directed cell differentiation include therapeutic cloning and regenerative medicine.
More Stem Cells Current Events and Stem Cells News Articles
Essentials of Stem Cell Biology, Second Edition

Essentials of Stem Cell Biology, Second Edition
by Robert Lanza (Editor), John Gearhart (Editor), Brigid Hogan (Editor), Douglas Melton (Editor), Roger Pederson (Editor), E. Donnall Thomas (Editor), James Thomson (Editor), Sir Ian Wilmut (Editor)

First developed as an accessible abridgement of the successful Handbook of Stem Cells, Essentials of Stem Cell Biology serves the needs of the evolving population of scientists, researchers, practitioners and students that are embracing the latest advances in stem cells. Representing the combined effort of seven editors and more than 200 scholars and scientists whose pioneering work has defined our understanding of stem cells, this book combines the prerequisites for a general understanding of adult and embryonic stem cells with a presentation by the world?s experts of the latest research information about specific organ systems. From basic biology/mechanisms, early development, ectoderm, mesoderm, endoderm, methods to application of stem cells to specific human diseases, regulation and...

Stem Cell Now

Stem Cell Now
by Christopher Thomas Scott (Author)

The essential account of the most important scientific advance—and most volatile ethical debate—of our time

While many believe stem cell research holds the key to curing a wide range of ailments, others see this research as opening a Pandora’s box that will devalue human life.

In Stem Cell Now, Christopher Scott—executive director of Stanford University’s Stem Cells and Society Program—lays out the scientific and ethical issues surrounding this national dilemma. Scott guides readers through the latest advances in stem cell research in clear, accessible language, telling the stories of the researchers who are exploring the potential of stem cells to cure cancer, grow new organs, and repair the immune system. He also leads readers through a...

The Stem Cell Divide: The Facts, the Fiction, and the Fear Driving the Greatest Scientific, Political, and Religious Debate of Our Time

The Stem Cell Divide: The Facts, the Fiction, and the Fear Driving the Greatest Scientific, Political, and Religious Debate of Our Time
by Michael Bellomo (Author)

There has been much recent debate about the merits, dangers, and nature of stem cell research. Some see in it the answer to every debilitating disease known to man, while others see it as a step away from human cloning.

While the battle has raged, research is moving ahead, and California has already passed a measure that will give $3 billion in support to stem cell research. But as politics, religion, and the media weigh in on this complex issue, more and more of the scientific reality of stem cell research is getting lost. In the search for the truth about stem cell science, the author has interviewed the scientists whose cutting-edge research is at the very heart of this hot-button issue. The book explains what they have accomplished so far, what they're currently doing, and what...

Human Stem Cell Manual: A Laboratory Guide

Human Stem Cell Manual: A Laboratory Guide
by Jeanne F. Loring (Editor), Robin L. Wesselschmidt (Editor), Philip H. Schwartz (Editor)

Stem cells are self-replicating and undifferentiated, meaning their function is not yet cell, tissue, or organ-specific. Due to the unique nature of these cells, research into their biology and function holds great promise for therapeutic applications through replacement or repair of diseased and damaged cells. This reader-friendly manual provides a practical "hands on" guide to the culture of human embryonic and somatic stem cells. By presenting methods for embryonic and adult lines side-by-side, the authors lay out an elegant and unique path to understanding the science of stem cell practice. The authors begin with a broad-based introduction to the field, and also review legal and regulatory issues and patents. Each experimental strategy is presented with an historical introduction,...

Stem Cell Research: Medical Applications And Ethical Controversy (The New Biology)

Stem Cell Research: Medical Applications And Ethical Controversy (The New Biology)
by Joseph, Ph.D. Panno (Author)

This is an informative reference to the technological advances, applications, and issues of stem cell research. The past few years have seen controversy and debate surrounding stem cell research. Because skin cells have the capability to divide - unlike most of the cells in our body - our skin can heal itself through the division of cells. Scientists have attempted to apply this concept to major organs, trying to see if stem cells can be used to make the repairs that post-mitotic cells cannot. "Stem Cell Research" is a comprehensive and interesting introduction to this popular new science for non-experts. Explaining how stems cells can be obtained from several places, including skin, bone marrow, and most usefully, embryos, this book covers all the fundamental aspects of stem cell...

Cell of Cells: The Global Race to Capture and Control the Stem Cell

Cell of Cells: The Global Race to Capture and Control the Stem Cell
by Cynthia Fox (Author)

Publication Date is March 26, 2007

The Stem Cell Dilemma: Beacons of Hope or Harbingers of Doom?

The Stem Cell Dilemma: Beacons of Hope or Harbingers of Doom?
by Leo Furcht (Author), William Hoffman (Author)

TodayÕs scientists are showing us how stem cells create and repair the human body. Unlocking these secrets has become the new Holy Grail of biomedical research. But behind that search lies a sharp divide. Stem cells offer the hope of creating or repairing tissues lost to age, disease, and injury. Yet because of this ability, stem cells hold the potential to incite an international biological arms race. THE STEM CELL DILEMMA will tell you everything you ever wanted to know about stem cells: what they are, how they work, and why their use has become so controversial. We are standing at a scientific crossroads, the likes of which the world has never seen. It is a moment that will change forever the practice of medicine and the future of life as we know it.

Mesenchymal Stem Cells: Methods and Protocols (Methods in Molecular Biology)

Mesenchymal Stem Cells: Methods and Protocols (Methods in Molecular Biology)
by Darwin J. Prockop (Editor), Donald G. Phinney (Editor), Bruce A. Bunnell (Editor)

For over forty years, mesenchymal stem cells (MSCs) have been scrutinized and studied, garnering much attention due to their broad therapeutic efficacy. In Mesenchymal Stem Cells: Methods and Protocols, leaders in the field were assembled to contribute detailed methodologies for the isolation and characterization of human and rodent MSCs. Recently, these vital cells have shown therapeutic benefits in the treatment of myocardial infarction, stroke, lung diseases, spinal cord injury and other neurological disorders, thus promising a boundless future in their study.

Cutting edge and easy to use, Mesenchymal Stem Cells: Methods and Protocols is the perfect resource for scientists attempting to pursue this important and ever-developing field of research.



The Stem Cell Controversy: Debating the Issues (Contemporary Issue Series)

The Stem Cell Controversy: Debating the Issues (Contemporary Issue Series)
by Michael Ruse (Editor), Christopher A. Pynes (Editor)

Stem cell research is headline news. Researchers are eager to move forward, state governments and private foundations are rushing to support it, and the sick and afflicted are desperate for its benefits. Yet powerful forces in our society—led by President George W. Bush—find it morally troubling and they are doing all in their powers to restrict its development beyond a very limited scale. Stem cells have the potential to develop into different parts of the body—skin, bone, nerves, blood, and more. Scientists usually harvest them from aborted fetal tissue or newly fertilized cells. This procedure has proved very unacceptable to the religious right. They argue that even a newly fertilized cell is fully human and has all of the rights of full-grown adults, and they find any use of...

Stem Cell Wars: Inside Stories from the Frontlines

Stem Cell Wars: Inside Stories from the Frontlines
by Eve Herold (Author), George Daley Dr. (Foreword)

Americans have become the victims of misinformation about stem cell research. Over the last few years, the stem cell debate has been intensely political, religious, and confusing to many people. Now, Eve Herold explains what this science is all about, who is for and against it, and why it must go forward. She pulls together fascinating stories to highlight every aspect of this multifaceted field. She exposes the politics of stem cell research and demonstrates how the outcome of the debate could ultimately affect all of us. Packed with real-life stories of the people caught up in this groundbreaking struggle, Stem Cell Wars cuts through the noise and sets the standard for future debate.

© 2009 BrightSurf.com