Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

One gene provides fruit fly both antenna and color vision

06.04.2006
Brilliant reception

A team of researchers that includes biologists from Washington University in St. Louis has discovered that a gene involved in the development and function of the fruit fly antenna also gives the organism its color vision.


Pretty fly - for a fruit fly. The areas stained blue are regions in the fruit fly where the spineless gene is expressed. WUSTL biologists Ian and Dianne Duncan have spent years making discoveries of how the gene is involved in making the fruit fly antenna. Now they are part of a team that has found that spineless plays a key role in the organism’s color vision.

Claude Desplan, Ph.D., professor of biology at New York University, and his students made the discovery and provided the data. Ian Duncan, Washington University professor of biology, and his wife, research assistant Dianne Duncan, provided the Desplan laboratory fruit fly (Drosophila) clones and mutants and technical assistance that helped locate where the gene, called spineless, is expressed in the retina.

The Duncans have a long history with the spineless gene. Their interest has been in the role spineless plays in directing development of the antenna, Drosophila’s primary olfactory organ. Years ago, they deleted the spineless gene and found that the mutants then produced a leg instead of an antenna.

"Spineless plays a key role in the antenna and maxillary palp, the two major olfactory organs of the fly," said Ian Duncan. "It’s also important in mechanosensory bristles and in the taste receptors of the legs, wings, and mouth parts. There has been a sensory theme to the gene, and now we learn from Claude’s work that it plays a key role in color vision."

In humans the closest known homolog (counterpart) is the arylhydrocarbon (’dioxin’) receptor, a key protein in human health that senses a wide variety of synthetic compounds and then activates expression of detoxification genes. The dioxin receptor is studied closely in cancer biology and toxicology.

Recently, the Duncans had found a relationship between spineless and a gene called homothorax. Desplan’s group had shown that homothorax plays an important role in the Drosophila eye, and after hearing Ian Duncan make a presentation on the homothorax-spineless relationship in the antenna, the Desplan laboratory decided to study spineless in the eye.

The collaborators published their results in the March 9, 2006 issue of Nature.

Random pattern

The Drosophila retina is comprised of clusters of photosensitive cells called ommatidia. Two types of ommatidia are present: one is sensitive to long-wave light and the other to short-wave light. This difference is due to the expression of different light-sensitive pigments (rhodopsins) in the two central photoreceptor cells (R7 and R8) of each ommatidial cluster. Spineless determines the long-wave type by activating expression of rhodopsin-4 in R7 cells. In ommatidia where spineless is not expressed, R7 expresses the short-wave sensitive rhodopsin-3.

"The fascinating thing in this work is that the longer wave length sensitive ommatidia are randomly positioned," said Duncan. "About 70 percent of the ommatidia sense longer wavelength and 30 percent sense short-wave length. It’s been a mystery how you generate a random pattern like that and still have that ratio."

Using the tools that the Duncan laboratory provided, Desplan’s group mapped the regulatory region in the spineless gene that drives the random pattern mechanism.

"Nobody knew what controlled this random pattern," said Dianne Duncan. "Now we know it’s spineless. We’ve known for a while that spineless has several sensory functions and we thought it might be a bit underrated in developmental biology. Now we add color vision to its duties."

Spineless also appears to control communication between the R7 and R8 photoreceptors. "It has been known for some time that the expression of rhodopsin genes in R7 and R8 is coupled with the particular genes expressed in R8 being determined by the adjacent R7 cells," said Ian Duncan.

"An additional important finding in the paper is that spineless controls this signaling between R7 and R8."

Link to human odor perception

The Duncans will continue to look for other genes that spineless controls in making an antenna. They have shown that spineless acts together with two other factors, Homothorax and Distalless, and identified downstream target genes by virtue of their having clustered binding sites for these factors. And they are looking into similarities between spineless and the mammalian dioxin receptor. In a collaboration with a University of Wisconsin researcher, they have put the mammalian dioxin receptor gene into Drosophila, where, surprisingly, it specifies the making of an antenna.

"When you think about it, the antenna is quite special," Dianne Duncan said. "It contains many proteins not expressed anywhere else in the fly. These include many odor receptor proteins that are expressed in subsets of cells within the antenna. Our hope is that by unraveling how development of the Drosophila antenna is controlled, we will gain important insights into how human odor perception works."

Tony Fitzpatrick | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>