Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Keeping biological tubes in check: New insights into tube size morphogenesis

24.01.2006


The function of tubular organs like the kidneys, lungs, and vessels of the vascular system is critically dependent on the length and diameter of the tubular branches of which they are composed. Several devastating pathological conditions like polycystic kidney disease and ischemias have been intimately linked to the aberrant sizes of tubular organs. Yet the underlying cellular and molecular mechanisms that control tube size are poorly understood, and, consequently, drugs that intervene in tubular organ disorders are lacking.



Over the past few years, the tracheal system of the fruit fly Drosophila has provided important general insights into epithelial organ morphogenesis. The fly’s tracheal system is a tubular network that functions in respiration by transporting oxygen throughout the insect body. In two separate new studies, researchers have taken advantage of the usefulness of the Drosophila tracheal system as a model for understanding the development of tubular organs. Both studies point to the important role played in this process by the luminal extracellular matrix (ECM)--a scaffold of sorts that provides structure to surrounding cells and tissues. Past work had shown that inside the tracheal tube, or lumen, the polysaccharide molecule chitin forms a cylinder that is essential for the coordinated dilation of the surrounding epithelium to its normal mature size: Mutants lacking chitin show tubes with irregular diameter.

In one of the new studies, a group led by Christos Samakovlis at Stockholm University has revealed further evidence for an "instructive" function of the luminal ECM in tube size control. They found that while uniform expansion of tube diameter requires the growth of a luminal chitin scaffold, the subsequent modification of this chitinous mandrel by specialized enzymes (called chitin deacetylases) instructs the termination of tube elongation. Mutations in two genes encoding these enzymes disrupt tubular morphogenesis. The authors’ additional discovery that proper luminal localization of one of the chitin deacetylases requires a specialized secretory pathway and intact structures called paracellular septate junctions provides a mechanistic model for tracheal tube size regulation.


The other new study, from Stefan Luschnig and colleagues at Bayreuth University, Germany, and at Stanford University, reports a similar set of findings. These researchers also identified the two chitin deacetyase genes as specifically controlling tube length. As did the Samakovlis group, the researchers found that mutations in these genes, called serpentine (serp) and vermiform (verm), cause excessively elongated and tortuous tracheal tubes. Unlike previously characterized genes, serp and verm are not required for producing chitin, but rather are required for its normal fibrillar structure. The findings of the two groups suggest that tube length is controlled by modulating physical properties of the chitin cylinder. These properties may be sensed by tracheal cells, mediating the restriction of cell elongation.

Given the many similarities in the developmental mechanisms and cellular designs of tubular organs across species, the distinct roles of the luminal ECM in tracheal tube size control provide new leads in the investigation of lumen size regulation in a variety of tubular organs.

Heidi Hardman | EurekAlert!
Further information:
http://www.current-biology.com

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Supercomputing helps researchers understand Earth's interior

23.05.2017 | Earth Sciences

Study identifies RNA molecule that shields breast cancer stem cells from immune system

23.05.2017 | Life Sciences

Turmoil in sluggish electrons’ existence

23.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>