Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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


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:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>