Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Balancing act

12.01.2009
A recently discovered protein works behind the scenes to confer much-needed stabilization to an essential developmental pathway

Early in development, embryos transition from being simple spheres of cells into more structured forms in which the foundations of body patterning—such as distinct dorsal (back) and ventral (front) sides—have been established.

Dorsal–ventral patterning is primarily established by BMP signaling factors, which exhibit a gradient of activity along the length of the embryo: elevated BMP activity induces ventral development, while reduced BMP signaling induces dorsality. Reduction in BMP activity is mediated by a structure known as the Spemann organizer, which secretes factors like Chordin, which inactivates BMP and drives dorsalization.

However, BMP also represses Chordin expression, creating a seemingly fragile regulatory situation in which transient upregulation of Chordin could trigger a chain reaction of uncontrolled Chordin upregulation, with catastrophic results for body patterning.

This isn’t the case; in fact, this process is surprisingly robust. Yoshiki Sasai of the RIKEN Center for Developmental Biology in Kobe, suspected that additional failsafe mechanisms must exist to stabilize Chordin–BMP regulation, and decided to investigate the involvement of a protein recently discovered by his team, ONT1, which they thought might play a role in body patterning (1).

ONT1 is produced and secreted by cells in the dorsal region of the embryo, where it appears to directly regulate Chordin function, and Sasai’s team found that frog embryos with reduced ONT1 activity are far more vulnerable to excessive dorsalization in the presence of abnormally elevated Chordin levels. “We were really surprised to see how drastically the stability collapsed after knocking down ONT1 function,” he says.

They determined that ONT1 not only interacts directly with Chordin, but also binds to an enzyme known to degrade Chordin, and came to the surprising conclusion that ONT1 acts as a bridge that links the two proteins and thereby expedites destruction of the dorsalization signal. “There are a number of examples of intracellular scaffolds,” says Sasai, “but ONT1 is a rare example of a secreted scaffold for enzymes.”

There is another recently identified pathway for the regulation of dorsal–ventral patterning, mediated by ADMP, a protein that reduces Chordin levels by activating BMP receptors, and ONT1 and ADMP appear to regulate parallel but independent pathways for ensuring robust control of dorsalization in the embryo.

The researchers now hope to delve deeper into this more complex model of organizer regulation. “One important approach will be to establish a mathematical model for this integrated view of organizer function,” says Sasai, “particularly to explain these phenomena in a spatial and real-time fashion.”

Reference

1. Inomata, H., Haraguchi, T. & Sasai, Y. Robust stability of the embryonic axial pattern requires a secreted scaffold for Chordin degradation. Cell 134, 854–865 (2008).

The corresponding author for this highlight is based at the RIKEN Laboratory for Organogenesis and Neurogenesis

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/621/
http://www.researchsea.com

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>