New findings reveal the surprisingly complex protein-coding capacity of the human cytomegalovirus, or HCMV, and provide the first steps toward understanding how the virus manipulates human cells during infection.
The genome of the HCMV was first sequenced over 20 years ago, but researchers have now investigated the proteome—the complete set of expressed proteins—of this common pathogen as well.
HCMV is an incredibly successful virus, and it infects most humans on the planet. Birth defects and disease, however, are only known to occur in newborn infants and adults with compromised immune systems, respectively. But, the pathogen also has one of the largest viral genomes on record, with a massive 240,000 base pairs of DNA. (For comparison, the genome of the poliovirus only contains about 7,500 base pairs.)
Noam Stern-Ginossar from the University of California in San Francisco, along with colleagues from the United States and Germany, used a combination of techniques, including ribosome profiling and mass spectrometry, to study HCMV's proteome. The method could be used to investigate proteins produced by other viruses as well, they say.
The researchers' findings appear in the 23 November issue of the journal Science, which is published by AAAS, the nonprofit science society.
"The genome of a virus is just a starting point," explained Jonathan Weissman from the University of California, a co-author of the Science report. "Understanding what proteins are encoded by that genome allows us to start thinking about what the virus does and how we can interfere with it… Each of the proteins we've identified has the potential to tell us how this virus is manipulating its host cell."
Stern-Ginossar and the other researchers suspected that existing maps of HCMV's protein-coding potential, based largely on computational methods, were far from complete. So, they began mapping the positions of ribosomes—the cellular organelles in which proteins are synthesized—during an HCMV infection of human fibroblast cells. With the resulting map, Stern-Ginossar and her colleagues discovered templates for hundreds of previously unidentified proteins that were encoded in corresponding DNA segments of the viral genome, known as open reading frames.
Surprisingly, the researchers found that many of these open reading frames encode for exceptionally short protein sequences (fewer than 100 amino acids). And some of the newly identified open reading frames were even hiding inside other open reading frames, they say.
"A key finding of our work is that each of these templates can encode more than one protein," said Annette Michalski from the Max Planck Institute of Biochemistry in Martinsried, Germany, another co-author of the Science report. "And these extremely short proteins might be more common than we expect."
The researchers applied mass spectrometry to confirm the presence of many unknown viral proteins that had been predicted by mapping the ribosome positions.
In the future, this coupling of ribosome profiling with mass spectrometry might be used to investigate the proteomes of other complex viruses. Eventually, such information could be used to understand how different viruses hijack their hosts' cells for their own purposes.
The report by Stern-Ginossar et al. was supported by a human frontier science program postdoctoral fellowship, the Howard Hughes Medical Institute and the Max-Plank Society.
The American Association for the Advancement of Science (AAAS) is the world's largest general scientific society, and publisher of the journal, Science as well as Science Translational Medicine and Science Signaling. AAAS was founded in 1848, and includes some 261 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world, with an estimated total readership of 1 million. The non-profit AAAS is open to all and fulfills its mission to "advance science and serve society" through initiatives in science policy; international programs; science education; and more. For the latest research news, log onto EurekAlert!, www.eurekalert.org, the premier science-news Web site, a service of AAAS.
Natasha Pinol | EurekAlert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
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...
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...
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....
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,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses