Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Checking how cells grow

24.04.2003


New research dismisses a widely held assumption about how cells grow



Research published today in Journal of Biology challenges an assumption about cell growth that underpins modern cellular biology. Ian Conlon and Martin Raff, of University College London, show that mammalian cells do not regulate their size in the way scientists have assumed they do since the 1970s.
Conlon and Raff conducted a series of experiments, using Schwann cells from the sciatic nerve of rats, to establish how mammalian cells control their size and ‘decide’ when to divide. This processes of cell size, growth and division has been widely studied in yeast for thirty years, and many aspects are the same in the two types of cell. Both yeast and mammalian cells are known to be able to maintain a constant average size as they grow and divide. It has therefore been assumed that the ‘checkpoints’ yeast cells use to ensure that they divide when they reach the correct size are mirrored by checkpoints in mammalian cells, but that assumption had not been tested experimentally - until now.

Using precise measurements, Conlon and Raff found key differences in the ways yeast and mammalian cells grow. Yeast cells grow exponentially, doubling in size over a fixed time period, but mammalian cells grow in a linear way, getting larger by the same amount each day; this means that the rate at which mammalian cells grow is the same regardless of the cell’s size, whereas in yeast big cells grow faster than small ones.



Previous research had shown that when moved to a nutrient-rich environment, yeast cells adjust quickly - within one cycle of growth and division. The average size of the cells increases when there are more nutrients available – so, yeast uses cell-size checkpoints to determine how large the cell should be before it divides.

It had been assumed that mammalian cells also use cell-size checkpoints. But Conlon and Raff found that when mammalian cells were moved to a nutrient-rich environment, it took approximately six divisions before cells grew to the average size they expected. This led them to conclude that mammalian cells do not use checkpoints based on their size to determine when to divide. Instead, Conlon and Raff suggest that mammalian cells ‘talk’ to each other, using extracellular signalling, to determine how large they should grow and when they should divide. “Animal cells hardly do anything without signals from other cells” says Raff.

The new research makes clear that there are important differences between the way yeast and mammalian cells coordinate cell growth and size. These differences make sense biologically. Yeast is a single-celled organism - cells are independent of each other and can grow and divide as fast as the nutrients in their environment can support. Animal cells are part of a larger organism, so their growth affects the good of the whole animal, and it makes good biological sense that this is controlled by signals from other cells.

Understanding cell growth and proliferation is of profound importance for biology and has implications for tackling disease, including cancer.

Grace Baynes | BioMed Central Limited
Further information:
http://jbiol.com/content/2/1/7

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | 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

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>