Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new molecule for high-resolution cell imaging

26.05.2014

Like our own bodies, cells have their own skeletons called 'cytoskeletons' and are made of proteins instead of bones.

These network-like structures maintain the cell's shape, provide mechanical support, and are involved in critical processes of the cell's lifecycle. The cytoskeleton is an object of intense scientific and medical research, which often requires being able to observe it directly in cells.

Ideally, this would involve highly-fluorescent molecules that can bind cytoskeletal proteins with high specificity without being toxic to the cell. Publishing in Nature Methods, EPFL scientists have exploited the properties of a new fluorescent molecule, also developed at EPFL, to generate two powerful probes for the imaging of the cytoskeleton with unprecedented resolution. These probes pave the way for the easier and higher quality imaging of cells, offering many scientific and medical advantages.

The cytoskeleton is a large structure inside cells that provides them with mechanical support, keeps their three-dimensional shape and internal organization, and enables them to move and divide. It consists of three major sub-structures inside the cell, which are made up of long, filamentous proteins: tubulin and actin.

Current techniques for observing the cytoskeleton can be difficult to get into living cells, can be toxic, and are usually limited in resolution and duration, since the signal wears off over time. A common technique is fluorescence microscopy, where fluorescent molecules ('probes') are attached to cell structures and then 'lit up' against a dark background.

The team of Kai Johnsson at EPFL has developed novel fluorescent probes that can easily enter live cells, are non-toxic, have long-lasting signals, and most importantly, offer unprecedented image resolution. In 2013, the researchers developed a fluorescent molecule called silicon-rhodamine (SiR), which switches 'on' only when it binds to the charged surface of a protein like the ones found on the cytoskeleton. When SiR switches 'on', it emits light at far-red wavelengths.

The challenge was getting SiR to bind specifically to the cytoskeleton's proteins, actin and tubulin. To achieve this, the scientists fused SiR molecules with compounds that bind tubulin or actin. The resulting hybrid molecules consist of a SiR molecule, which provides the fluorescent signal, and a molecule of a natural compound that can bind the target protein. One such compound was docetaxel, an anticancer drug that binds tubulin, and the other jasplakinolide, which specifically binds the cytoskeletal form of actin. Both compounds, which are used here in very low, non-toxic concentrations, can easily pass through the cell's membrane and into the cell itself.

The probes, named SiR-tubulin and SiR-actin, were used to visualize the dynamics of the cytoskeleton in human skin cells. Because the light signal of the probes is emitted in the far-red spectrum, it is easy to isolate from background noise, which generates images of unprecedented resolution when used with a technique called super-resolution microscopy.

An additional advantage is the practicality of the probes. "You just add them directly into your cell culture, and they are taken up by the cells", says Kai Johnsson. The probes also do not require any washing or preparation of the cells before administration or any subsequent washing steps, which greatly helps in maintaining the stability of their environment and their natural biological functions.

The scientists believe that they can extend their work into other types of proteins and tissues. "Cytoskeletal structures are imaged by biologists all the time", says Johnsson. "Up to now, no probes were available that would allow you to get high quality images of microtubules and microfilaments in living cells without some kind of genetic modification. With this work, we provide the biological community with two high-performing, high-contrast fluorogenic probes that emit in the non-phototoxic part of the light spectrum, and can be even used in tissues like whole-blood samples."

###

This work represents a collaboration between EPFL's Institute of Chemical Sciences and Engineering (ISIC), Institute of Bioengineering (IBI), and the Bioimaging and Optics Platform (BIOP), with the National Centre of Competence in Research (NCCR) in Chemical Biology; the Max-Planck Institutes for Biophysical Chemistry (Göttingen) and of Molecular Physiology (Dortmund); the Friedrich-Schiller-University's Institute of Organic Chemistry (Jena); and the Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA) (Vienna).

Reference

Lukinavičius G, Reymond L, D'Este E, Masharina A, Göttfert F, Ta H, Güther A, Fournier M, Rizzo S, Waldmann H, Blaukopf C, Sommer C, Gerlich DW, Arndt HD, Hell SW, Johnsson K. Fluorogenic probes for live-cell imaging of the cytoskeleton. Nature Methods 25 May 2014. DOI: 10.1038/nmeth.2972

Nik Papageorgiou | Eurek Alert!
Further information:
http://www.epfl.ch

Further reports about: EPFL Ecole Molecular Polytechnique actin cytoskeleton fluorescent proteins spectrum structures

More articles from Life Sciences:

nachricht Faster detection of pathogens in the lungs
24.06.2016 | Universität Zürich

nachricht How yeast cells regulate their fat balance
23.06.2016 | Goethe-Universität Frankfurt am Main

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First experimental quantum simulation of particle physics phenomena

Physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, building a bridge between high-energy theory and atomic physics. In the journal Nature, Rainer Blatt‘s and Peter Zoller’s research teams describe how they simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer.

Elementary particles are the fundamental buildings blocks of matter, and their properties are described by the Standard Model of particle physics. The...

Im Focus: Is There Life On Mars?

Survivalist back from Space - 18 months on the outer skin of the ISS

A year and a half on the outer wall of the International Space Station ISS in altitude of 400 kilometers is a real challenge. Whether a primordial bacterium...

Im Focus: CWRU physicists deploy magnetic vortex to control electron spin

Potential technology for quantum computing, keener sensors

Researchers at Case Western Reserve University have developed a way to swiftly and precisely control electron spins at room temperature.

Im Focus: Physicists measured something new in the radioactive decay of neutrons

The experiment inspired theorists; future ones could reveal new physics

A physics experiment performed at the National Institute of Standards and Technology (NIST) has enhanced scientists' understanding of how free neutrons decay...

Im Focus: Discovery of gold nanocluster 'double' hints at other shape changing particles

New analysis approach brings two unique atomic structures into focus

Chemically the same, graphite and diamonds are as physically distinct as two minerals can be, one opaque and soft, the other translucent and hard. What makes...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ERES 2016: The largest conference in the European real estate industry

09.06.2016 | Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

 
Latest News

Nanoscientists develop the 'ultimate discovery tool'

24.06.2016 | Materials Sciences

Russian physicists create a high-precision 'quantum ruler'

24.06.2016 | Physics and Astronomy

Hubble confirms new dark spot on Neptune

24.06.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>