Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers simulate molecular biological clock

17.01.2005


Researchers at New York University have developed a model of the intra-cellular mammalian biological clock that reveals how rapid interaction of molecules with DNA is necessary for producing reliable 24-hour rhythms. They also found that without the inherent randomness of molecular interactions within a cell, biological rhythms may dampen over time. These findings appeared in the most recent issue of the Proceedings of the National Academy of Sciences (PNAS).



Daniel Forger, an NYU biologist and mathematician, and Charles Peskin, a professor at NYU’s Courant Institute of Mathematical Sciences and Center for Neural Science, developed a mathematical model of the biological clock that replicates the hundreds of clock-related molecular reactions that occur within each mammalian cell.

Biological circadian clocks time daily events with remarkable accuracy--often within a minute each day. However, understanding how circadian clocks function has proven challenging to researchers. This is partly because the 24-hour rhythm is an emergent property of a complex network of many molecular interactions within a cell. Another complication is that molecular interactions are inherently random, which raises the question how a clock with such imprecise components can keep time so precisely. One way to combat molecular noise is to have large numbers of molecular interactions, but this is limited by the small numbers of molecules of some molecular species within the cell (for instance, there are only two copies of DNA).


To simulate the random nature of the biochemical interactions of the mammalian intra-cellular circadian clock, Forger and Peskin used the existing Gillespie method. The method tracks the changes in the integer numbers of each type of molecule of the system as these biochemical reactions occur. Modeling each type of molecule separately helped avoid mathematical assumptions in their model that may not be valid in real-life cells. Their model was validated with a large library of data on the concentrations of the molecular species within the mouse molecular clock at different times of the day and data on the behavior of mice with circadian clock mutations.

The results of their computer simulations showed that reliable 24-hour timekeeping can only be achieved if the regulatory molecules that influence gene expression bind and unbind to DNA quickly--typically, within a minute. In this way, the large number of bindings and unbindings helps to compensate for the small numbers of molecules involved. The researchers also found that having more molecules in the cell does not necessarily lead to more accurate timekeeping. Removing all the CRY1 molecules (CRY1 mutant) or removing all the CRY2 molecules (CRY2 mutant), while keeping all other molecular species unchanged, leads to more accurate timekeeping. While simulating the PER2 mutation, they found that circadian oscillations could only be sustained in the presence of molecular noise. This may help explain some of the conflicting experimental reports about the PER2 mutant.

"Without the rapidity of molecular interactions within these cells, the precision of the biological clock would be lost," explained Forger. "It is remarkable that a process occurring on the time scale of minutes can have such a profound effect on one that occurs over 24 hours."

James Devitt | EurekAlert!
Further information:
http://www.nyu.edu

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-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: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>