Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel mechanism to steer cell identities gives clue on how organisms develop

04.10.2016

Scientists discovered a new way in which microRNAs can determine the fate of cells in the course of their development. This could be a key to understanding how complex organisms are built, say researchers from the Institute of Molecular Pathology (IMP) in Vienna.

A class of genes called microRNAs are known to prevent gene expression. In a recent study, scientists could show that down-regulating genes through microRNAs can determine unique properties of specific cells in an unexpected way. This finding was now reported in the journal “Genes & Development”.


Luisa Cochella and Model organism C.elegans

IMP/Beck

“We set out from a curious observation in the nematode worm C. elegans”, explains Luisa Cochella. “We noticed that the gene mir-791 was expressed specifically in neurons we knew were responsible for the detection of carbon dioxide.” The tiny worm is a common model organism because its anatomy and cell functions are very well-understood and can be observed easily under a microscope. When the worms detect carbon dioxide, they start moving in a characteristic way, giving the scientists an easy tool to indirectly “watch” molecular processes by observing the worms’ behaviour.

When the scientists removed mir-791 from the worms, the animals had trouble responding to carbon dioxide. Normally, mir-791 prevents the expression of two genes exclusively in the neurons that detect carbon dioxide, while these same two genes are expressed in pretty much all other cells of the worm. When this repression mechanism fails, the carbon dioxide sensing neurons do not work properly and animals cannot respond adequately to an environmental cue that, in its natural environment, could determine whether the worm lives or dies. The question how the identity of cells is determined in the course of their development, however, goes far beyond nematodes – it is a fundamental question in biology.

The cells that form our bodies belong to hundreds of different cell types that are shaped by the combinations of genes they express. For example, hemoglobin is produced in red blood cells where it is necessary for oxygen transport, while neurotransmitter receptors are made in neurons where they allow these cells to communicate with each other. On the other hand, a number of genes that are required for more common functions of cells are expressed by most, if not all cells. These are called ubiquitous genes.

In rare cases, ubiquitous genes are not expressed in a specific cell type, where reduced levels of these genes are necessary for the correct function of this particular cell type. The unique properties of a cell can therefore not only be specified by the genes it expresses, but also by the genes it prevents from being expressed. However, the mechanisms that underlie the highly specific repression of genes in some cells have remained puzzling, which is why this study is important.

What was characterised as a developmental mechanism could also be relevant for evolution. The responses of different animals to carbon dioxide vary a lot – some are attracted to it because it is linked to food sources, others flee from it because carbon dioxide is often high in environments with little oxygen. “Given this, our work has the additional implication that microRNAs may be good candidates to give species new tools to adapt to different environments”, says Cochella, who points at the known fact that microRNAs evolve faster than the bigger protein-coding genes.

The IMP, with 15 groups focusing on a diversity of fundamental research questions, provided the perfect place for Cochella and her team to carry out this study. The collaboration with co-author Manuel Zimmer, who has long established ways to quantitatively measure behavioural responses in C. elegans, was instrumental to this project.

In addition, this study provides insight into understanding microRNA functions. “In C. elegans there are between 150 and 200 miRNAs but we only know the functions of 25 or so of them”, says Cochella. This is not only true for the worm, a similarly low fraction of miRNAs has been characterized out of the hundreds found in humans, even though as a whole, miRNAs are essential for animal development and function. This study hints at why miRNA functions have been difficult to uncover: many miRNAs may be only expressed in restricted cell types and finding their functions may require methods as precise as those used in the worm to know exactly which and how cells are affected.

Original Publication
Tanja Drexel, Katharina Mahofsky, Richard Latham, Manuel Zimmer and Luisa Cochella: Neuron-type specific miRNA represses two broadly expressed genes to modulate an avoidance behavior in C. elegans. Genes & Dev., Published in Advance September 29, 2016, doi: 10.1101/gad.287904.116

Image caption
“Luisa Cochella studies the ways in which genes specify different cell identities, using a tiny worm as a model organism. The microscope image here reveals the cells that allow the worm to smell carbon dioxide.” © IMP/Beck

About Luisa Cochella
Luisa Cochella studies the ways in which gene expression must be regulated during development in order to specify the properties of the hundreds of different cell types that give rise to a complex multicellular animal. She studies this in the tiny nematode worm C. elegans. This worm is an extremely useful model organism to address this question because it is made of relatively few cells that can easily be followed during development.
Luisa Cochella did her undergraduate studies at Universidad de Buenos Aires in her home country Argentina, followed by PhD studies at Johns Hopkins School of Medicine in Baltimore (USA). After her post-doctoral work at Columbia University in New York (USA), Dr. Cochella took the next step in her outstanding academic career and became a group leader at the Research Institute of Molecular Pathology (IMP) in Vienna (Austria), in January 2013.

About the IMP
The renowned Research Institute of Molecular Pathology (IMP) in Vienna is a basic biomedical research institute largely sponsored by Boehringer Ingelheim. With over 200 scientists from 37 nations, the IMP is committed to scientific discovery of fundamental molecular and cellular mechanisms underlying complex biological phenomena. Research areas include cell and molecular biology, neurobiology, disease mechanisms and computational biology.

Contact
Dr. Benedikt Mandl
IMP - Communications
Tel. +43 1 79730 3627
benedikt.mandl@imp.ac.at

www.imp.ac.at

Weitere Informationen:

http://www.imp.ac.at/pressefoto-Cochella

Dr. Heidemarie Hurtl | idw - Informationsdienst Wissenschaft

Further reports about: IMP Molekulare Pathologie carbon dioxide cell types elegans genes miRNAs neurons

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>