Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Controlling body size by regulating the number of cells

06.08.2003


Why are elephants bigger than mice? The main reason is that mice have fewer cells. Research published in Journal of Biology this week uncovers a key pathway that controls the number of cells in an animal, thereby controlling its size.



Ernst Hafen and his colleagues from the University of Zürich used fruit flies to investigate the role of the insulin-signalling pathway and in particular a molecule called FOXO. If insulin signalling is reduced, for example by starving developing fly larvae, FOXO activity increases; this then reduces the number of cells in the developing flies, causing them to be smaller.

Mammals have similar a signalling pathway, and it has been suggested to have a role in tumour formation. Hafen’s work gives us more insights into how disruption of FOXO function can lead to cancer.


The researchers used a combination of genetic techniques, over expressing FOXO in parts of the fly and analysing flies that contained no functional FOXO protein, to investigate what FOXO does. They found that flies with no functional FOXO looked normal but were more sensitive to oxidative stress, thought to be a cause of ageing. Increasing the amounts of highly active FOXO protein in the developing fly eye caused many of the eye cells to die. However, the real clue to FOXO’s function came from studying the effect of removing functional FOXO protein from flies that have a reduced ability to signal downstream of insulin.

Normally, reducing insulin signalling in developing flies causes these flies to become smaller as they have fewer, smaller cells. Yet without FOXO, these flies do not suffer such a severe size reduction. This is because they have more cells than normal insulin signalling pathway mutants. These experiments suggest that FOXO plays a role in reducing the number of cells in the developing fly if insulin is not present, by inhibiting cell division.

Hafen and his co-authors write, “In this study we provide genetic evidence that the Drosophila FOXO homolog, dFOXO is an important downstream effector of Drosophila insulin signalling and regulator of stress resistance”.

The insulin-signalling pathway may provide a crucial link between nutrient availability, stress and growth, thus allowing animals to respond appropriately to their environment.

Gemma Bradley | alfa
Further information:
http://www.biomedcentral.com

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
21.08.2017 | 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

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>