Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why the thumb of the right hand is on the left hand side

26.05.2009
A researcher of the University of Innsbruck elucidates an important developmental mechanism

It is the concentration of a few signaling molecules that determines the fate of individual cells during the early development of organisms. In the renowned journal Current Biology, a team of molecular biologists led by Pia Aanstad of the University of Innsbruck reports that a variety of molecular mechanisms accounts for the interpretation of the concentration of the signaling molecule Hedgehog.

The development of an organism is a complex process to which a dozen or hundreds of signaling molecules contribute. Some of these molecules have dozens of functions in the fruit fly and in humans alike. One of these molecules – Hedgehog – controls the development of, for example, the extremities, the central nervous system, the teeth, eyes, hair, lung and the gastrointestinal tract. "What is most remarkable: The cells are told what to do not only because the molecule is present but also by the different concentrations of the molecules in the tissue", says group leader Pia Aanstad of the Institute for Molecular Biology of the University of Innsbruck. "The concentration of Hedgehog makes the thumb of the right hand grow on the left hand side and the thumb of the left hand grow on the right hand side." Thus, scientists define Hedgehog as a morphogen – a signal that is concentration-dependent and controls the pattern formation of an organism. A mutation in this signaling pathway induces dramatic and embryonically lethal malformations in the early developmental stage such as the formation of just one central eye.

Defects in the Hedgehog signaling pathway in humans are a cause for one of the most common birth defects – holoprosencephaly. "Hedgehog genes are not new in evolution and the signaling pathway functions in the fly, mouse, fish and in humans similarly", says Pia Aanstad. In her research work she focuses on the zebra danio or zebra fish. Due to the short developmental cycle, the scientists are able to observe the development of the small tropic fish in fast motion. "We want to better understand how the cells process the signals of the signaling molecules and how they react."

Mutants do not react to high concentrations

Already during her time as a post doc in San Francisco, U.S., Pia Aanstad discovered a mutated zebra fish whose Hedgehog signaling pathway was disrupted. The fish showed a genetic alteration at the so-called Smoothened (Smo) protein, which is located at the cell membrane and transfers the Hedgehog signal into the cell. In 2005, Aanstad and her colleagues published a paper in the renowned journal Nature, in which they showed that Smo is concentrated at cilia (cellular projections) and also functions at the cilium. "By using high-resolution fluorescence microscopy, we have now shown that in the new mutants a small genetic alteration at the extracellular part of this protein inhibits localization in the cilia and that while the cells identify the Hedgehog signals, they interpret the concentration incorrectly", explains Pia Aanstad. "This is evidence for the notion that cells use various molecular mechanisms for interpreting different Hedgehog concentrations." This fact may also be of importance for the diagnosis and treatment of certain cancers (basal cell carcinoma), where the constant up-regulation of the Hedgehog signal is responsible for uncontrolled cell growth. Aanstad published the findings together with her colleagues from the University of California, San Francisco in the journal Current Biology.

Successful scientist

Pia Aanstad started her research work at the Institute for Molecular Biology of the University of Innsbruck, headed by Prof. Dirk Meyer, last year. The Norwegian studied in England and continued her education at the Max-Planck Institute for Molecular Genetics in Berlin and at the Department of Biochemistry of the University of California. Together with her own research group in Innsbruck, she continues her research work on the Hedgehog signaling pathway. Because the question of which other mechanisms the cells use to interpret the concentration of signaling proteins has not been answered so far.

Pia Aanstad | EurekAlert!
Further information:
http://www.uibk.ac.at

More articles from Life Sciences:

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

nachricht First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>