Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

RNA Interference Found in Budding Yeasts

14.09.2009
FINDINGS: Some budding yeast species have the ability to silence genes using RNA interference (RNAi). Until now, most researchers thought that no budding yeasts possess the RNAi pathway because Saccharomyces cerevisiae, the protoypical model budding yeast does not.

RELEVANCE: Some budding yeasts cause human diseases, while other budding yeasts are used in research as models for more complicated organisms, in industry to create beer and biofuels, and in pharmaceuticals to produce drugs and vaccines. The ability to study RNAi in yeast and to use RNAi to alter yeast protein production could yield benefits for each of these fields.

RNAi, a key biochemical pathway in the genetic control networks of most organisms, has now been discovered in Saccharomyces castellii, a close relative of the prototypical budding yeast S. cerevisiae, and in Candida albicans, a common human pathogen.

Budding yeasts are used in research as models for more complicated organisms, in industry to create beer and biofuels, and in pharmaceuticals to produce drugs and vaccines. The ability to study RNAi in yeast and to use RNAi to alter the yeast’s protein production may be beneficial for all these fields.

The finding is reported in the September 10 issue of Science Express.

“For a long time, people thought that budding yeast didn’t have RNAi at all because Saccharomyces cerevisiae, which is the model budding yeast, doesn’t have RNAi,” says Kathleen Xie, an author on the paper and an undergraduate researcher in the lab of Whitehead Member David Bartel. “And this was kind of a pity because we didn’t have a budding yeast model organism available for RNAi research.”

Yeast is a good model for the cells of more complicated organisms, including humans, because yeast genomes are easy to manipulate, yeast cells have a high rate of reproduction, and yeast cells have many functions and biochemical pathways in common with human cells.

One biochemical pathway found in more complex organisms is the RNAi pathway, which is used by plants and many animals to silence genes of viruses and transposons, which are parasitic DNA elements. Two key proteins involved in RNAi—known as Dicer and Argonaute—are lacking in the S. cerevisiae genome. However, the lab of Kenneth Wolfe at Trinity College, Dublin, found that other budding yeasts do have Argonaute, indicating that they might have some form of RNAi. Wolfe brought up the finding to Bartel, who has devoted most of his lab’s effort to studying RNAi and related biochemical pathways.

Three Bartel researchers teamed up to determine whether any budding yeasts have RNAi capabilities, in collaboration with the laboratories of Wolfe and Whitehead Founding Member Gerald Fink. One of the species with the Argonaute protein is S. castellii. Anna Drinnenberg, a graduate student in the Bartel lab, developed S. castellii strains to study. Once the strains were established, Drinnenberg examined all of the small bits of RNA in S. castellii cells, looking for telltale signs that Dicer had been at work there.

Dicer, as its name implies, chops up long strands of double-stranded RNA into fairly uniform bits about 20 nucleotides long and hands them off to Argonaute. In S. castellii and in other budding yeasts, Drinnenberg found the correct size of chopped dsRNA in the yeast cells, yet was initially unable to detect a gene coding for a Dicer protein.

It turns out that the Dicer protein in these yeasts looks very different from the Dicer proteins of animals, plants and other fungi. “The fact that the Dicers of budding yeasts are so unusual probably explains why RNAi had gone undetected for so long in these species,” says Bartel, who is also a professor at MIT and a Howard Hughes Medical Institute (HHMI) investigator.

After the researchers confirmed that they had found the Dicer gene, David Weinberg, a graduate student in the Bartel lab, inserted the S. castellii Argonaute and Dicer genes into S. cerevisiae, which restored the RNAi pathway to this species that lost it.

Xie then observed that the restored RNAi pathway in S. cerevisiae prevented transposons from copying and reinserting themselves into the yeast’s genome. Transposons can harm the genome, and one of the main purposes of the RNAi pathway in other species including animals is to silence them.

“With a validated Dicer protein in S. castellii and reconstituted pathway in S. cerevisiae, we can now examine an RNAi pathway using all of the tools available for studying budding yeasts,” says Weinberg.

Bartel, agrees. “We can learn more about the RNAi pathway, just as yeast has taught us about many other biological processes. And there is a hope and assumption that researchers will now be able to use RNAi as a tool to learn more about these yeasts, including C. albicans.”

For Fink, this research also beautifully models one of Whitehead’s strengths--cooperation among researchers.

“This work was typical of collaboration at Whitehead,” says Fink, “You do the experiments first and worry about acclaim afterward, so the outcome is more synergistic than if the labs worked independently.”

Drinnenberg says that the teamwork was more than at the primary investigators’ level. “Particularly in the initial steps in working with yeast, I would go downstairs to the Fink lab and the lab of Whitehead Fellow Andreas Hochwagen to ask for advice, and talking to the people in their labs was very, very helpful.”

This research was funded by the National Institutes of Health (NIH), the National Science Foundation (NSF), and Boehringer-Ingelheim Fonds.

David Bartel is a Member at Whitehead Institute for Biomedical Research, where his laboratory is located and all his research is conducted. He is also a Howard Hughes Medical Institute Investigator and a professor of biology at Massachusetts Institute of Technology.

Gerald Fink’s primary affiliation is with Whitehead Institute of Biomedical Research, where his laboratory is located and all his research is conducted. He also is a professor of biology at Massachusetts Institute of Technology.

Full Citation:

“RNAi in budding yeast”

Science Express, September 10, 2009.

Ines A. Drinnenberg (1,2*), David E. Weinberg (1,2,3*), Kathleen T. Xie (1,2,3*), Jeffrey P. Mower (4), Kenneth H. Wolfe (4), Gerald R. Fink (1,3), David P. Bartel (1,2,3).

1. Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA.
2. Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
3. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
* These authors contributed equally to this work.

Nicole Giese | Newswise Science News
Further information:
http://www.wi.mit.edu

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>