Home  |  Top News  |  Most Popular  |  Video  |  Multimedia  |  News Feeds  |  Feedback
  Medicine  |  Nature & Earth  |  Biology  |  Technology & Engineering  |  Space & Planetary  |  Psychology  |  Physics & Chemistry  |  Economics  |  Archaeology
Top > Biology > Study Sheds Light on Genetic… >

Study Sheds Light on Genetic 'Clock' in Embryonic Cells

Published: November 13, 2012.
Released by McGill University  

As they develop, vertebrate embryos form vertebrae in a sequential, time-controlled way. Scientists have determined previously that this process of body segmentation is controlled by a kind of "clock," regulated by the oscillating activity of certain genes within embryonic cells. But questions remain about how precisely this timing system works.

A new international cross-disciplinary collaboration between physicists and molecular genetics researchers advances scientists' understanding of this crucial biological timing system. The study, co-authored by McGill University Prof. Paul François and Ohio State University Prof. Sharon L. Amacher and published in Developmental Cell, sheds light on the clock mechanism by providing the first real-time, visual evidence of how it operates at the level of individual cells.

While previous scientific studies have examined the oscillation phenomenon in the tissue of mouse embryos, the McGill and Ohio State researchers were able to observe and analyze it in single cells. To do so, they genetically modified zebrafish – a freshwater fish whose body is nearly transparent during early development, making its anatomy easy to observe. The researchers used a fluorescent marker in the transgenic fish and developed software tools to monitor the concentration of a certain "cyclic" protein, whose production rises and falls with the oscillating expression of the molecular clock genes.

It is known that cells communicate with neighboring cells through a messaging system known as the Notch signaling pathway. In their experiments with the zebrafish, the researchers cut off this inter-cellular communication network – enabling them to see how that would affect the oscillation pattern in individual cells and their neighbors.

These experiments revealed that cyclic protein concentrations in individual cells of the zebrafish continued to rise and fall, indicating that they continued to oscillate. With the inter-cellular signaling pathway blocked, however, the oscillations were no longer synchronized among neighboring cells. The cellular clocks were still ticking, in other words, but not in unison. This finding confirms that the Notch pathway serves to coordinate timing among cells – a crucial role, since the cells must act in concert in order to form vertebrae.

By observing normal zebrafish embryos, the researchers were also able to show that cells desynchronize their oscillations while performing cellular division, then later resynchronize with their neighbors as they proceed collectively to form vertebrae.

"In humans, defects in Notch signaling are associated with congenital developmental disorders called spondylocostal dysostosis, that are typified by scoliosis and trunk dwarfism caused by malformed ribs and vertebrae," Amacher notes. "Studies such as ours may provide insight into potential therapies for human disease. It is likely that many cells in our bodies - stem cells, cancer cells - have similar molecular oscillators that regulate response to environmental signals. By unraveling such molecular clocks, we can understand how to modify them and thus change the number of oscillating cells that respond to differentiating signals, providing tremendous insight for studies in stem cell and cancer biology and tissue engineering."

"The formation of the vertebral column is very important, because everything follows from that" in the development of vertebrates, François adds. A physicist, he developed the computer tools used to analyze video footage of the zebrafish embryos. Francois's research focuses on the modeling of physical properties of gene networks and their evolution – a field that has emerged at the nexus of biology and physics in recent years, following sequencing of the human genome and rapid growth in scientists' understanding of the processes inside cells.




The above story is based on materials provided by McGill University.

Translate this page: Chinese French German Italian Japanese Korean Portuguese Russian Spanish


comments powered by Disqus


Related »

Brain 
11/21/11 
★★ 
Implanted Neurons, Grown in the Lab, Take Charge of Brain Circuitry
Among the many hurdles to be cleared before human embryonic stem cells can achieve their therapeutic potential is determining …
Brain 
6/4/14 
Unlocking the Potential of Stem Cells to Repair Brain Damage
A QUT scientist is hoping to unlock the potential of stem cells as a way of repairing neural damage …
Bone 
9/14/11 
Shaping Up: Controlling a Stem Cell's Form Can Determine Its Fate
"Form follows function!" was the credo of early 20th century architects making design choices based on the intended use …
Cells 
4/21/13 
★★ 
Stem Cell Transplant Restores Memory, Learning in Mice
MADISON – For the first time, human embryonic stem cells have been transformed into nerve cells that helped mice …
Cells 
5/23/12 
Stem-cell-growing Surface Enables Bone Repair
ANN ARBOR, Mich.—University of Michigan researchers have proven that a special surface, free of biological contaminants, allows adult-derived stem …
Cell 
5/17/11 
★★★ 

Zebrafish Regrow Fins Using Multiple Cell Types, Not Identical Stem Cells
Stem 
8/19/14 
Zebrafish Help to Unravel Alzheimer's Disease
New fundamental knowledge about the regulation of stem cells in the nerve tissue of zebrafish embryos results in surprising …
Cells 
4/1/11 
Why Stem Cells Don't Just Want to Make Neurons
Research being presented today (01 April) at the UK National Stem Cell Network annual science conference provides another piece …
Human 
12/4/12 
New Method for Creating Long-lived Stem Cells Used for Bone Replacement
New Rochelle, NY, December 4, 2012—Human mesenchymal stem cells (hMSCs) can develop into bone cells and are useful for …
More » 
 
© Newsline Group  |  About  |  Privacy Policy  |  Feedback  |  Mobile