Forum for Science, Industry and Business

Dioxin-receptor network identified

A cell responds to pollutants - such as dioxin - via intricate and complex biochemical pathways beginning with the interaction of the pollutant molecule with a cell surface receptor. Christopher Bradfield and colleagues used yeast as a model system to elucidate the steps involved in the pathway that regulates vertebrate cell response to dioxin, the aryl hydrocarbon receptor (AHR) signal transduction pathway. To assess the molecules and pathways involved in the AHR pathway, the research group studied 4507 yeast "deletion" strains, each strain missing one gene from its genome. In this way Bradfield and colleagues identified 54 genes that had a significant influence on AHR response. Only two of these genes, termed modifiers, had been previously identified.

Though yeast does not naturally possess AHR, it is an ideal genetic model due to its small, well-characterized genome and similarity to vertebrate systems. Because yeast have been so well studied, the researchers were able to construct a "protein interaction network," (PIN) based on previously known interactions between the proteins encoded by the 54 modifier genes. The resulting map revealed groups of highly connected, related modifiers. The authors show that these modifiers group into five discrete biochemical steps in the pathway of dioxin signaling. Not only did they succeed in identifying potentially new genes involved in the signaling pathway but they were able to identify one of the modules as a previously undescribed nuclear step in the signaling pathway.


Citation: Yao G, Craven M, Drinkwater N, Bradfield CA (2004) Interaction Networks in Yeast Define and Enumerate the Signaling Steps of the Vertebrate Aryl Hydrocarbon Receptor. PLoS Biol: e65 DOI: 10.1371/journal.pbio.0020065

Christopher Bradfield | EurekAlert!
Further information:
http://www.publiclibraryofscience.org/
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0020065

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...