Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene limits learning and memory in mice

20.09.2010
Deleting a certain gene in mice can make them smarter by unlocking a mysterious region of the brain considered to be relatively inflexible, scientists at Emory University School of Medicine have found.

Mice with a disabled RGS14 gene are able to remember objects they'd explored and learn to navigate mazes better than regular mice, suggesting that RGS14's presence limits some forms of learning and memory.

The results were published online this week in the Early Edition of the Proceedings of the National Academy of Sciences.

Since RGS14 appears to hold mice back mentally, John Hepler, PhD, professor of pharmacology at Emory University School of Medicine, says he and his colleagues have been jokingly calling it the "Homer Simpson gene."

RGS14 is primarily turned on in one particular part -- called CA2 -- of the hippocampus, a region of the brain known for decades to be involved in consolidating new learning and forming new memories. However, the CA2 region lies off the beaten path scientifically and it's not clear what its functions are, Hepler says.

RGS14, which is also found in humans, was identified more than a decade ago. Hepler and his colleagues have previously shown that the RGS14 protein can regulate several molecules involved in processing different types of signals in the brain that are known to be important for learning and memory. They believe RGS14 is a key control protein for these signals.

To probe RGS14's functions, Sarah Emerson Lee, a graduate student working with Hepler, characterized mice whose RGS14 genes were disabled using gene-targeting technology. In collaboration with Serena Dudek, PhD, at the National Institute of Environmental Health Sciences, they examined how the CA2 region responded to electrical stimulation in the gene-altered mice.

Many researchers have examined how other parts of the hippocampus are involved in long-term potentiation, a strengthening of connections between neurons that can be seen after new memory formation or artificial stimulation in a culture dish. The CA2 region is distinct from other regions for being resistant to long-term potentiation, and neurons within CA2 are able to survive injury by seizures or stroke more than neurons in other parts of the hippocampus.

The researchers were surprised to find that, in mice with a disabled RGS14 gene, the CA2 region was now capable of "robust" long-term potentiation, meaning that in response to electrical stimulation, neurons there had stronger connections. On top of that, the ability of the gene-altered mice to recognize objects previously placed in their cages was enhanced, compared to normal mice. They also learned more quickly to navigate through a water maze to a hidden escape platform by remembering visual cues.

"A big question this research raises is why would we, or mice, have a gene that makes us less smart – a Homer Simpson gene?" Hepler says. "I believe that we are not really seeing the full picture. RGS14 may be a key control gene in a part of the brain that, when missing or disabled, knocks brain signals important for learning and memory out of balance."

The lack of RGS14 doesn't seem to hurt the altered mice, but it is still possible that they have their brain functions changed in a way that researchers have not yet been able to spot. Besides being resistant to injury by seizure, certain types of CA2 neurons are lost in schizophrenia, and loss of another gene turned on primarily in the CA2 region leads to altered social behaviors, Hepler notes.

"This suggests that these mice may not forget things as easily as other mice, or perhaps they have altered social behavior or sensitivity to seizures," he says. "But not necessarily."

Lee is investigating some of these possibilities now.

"The pipe dream is that maybe you could find a compound that inhibits RGS14 or shuts it down," he adds. "Then, perhaps, you could enhance cognition."

At Emory, collaborators included Kerry Ressler, MD, PhD, associate professor of psychiatry and behavioral sciences, Yoland Smith, PhD, research professor of neurology (both at Yerkes National Primate Research Center), David Weinshenker, PhD, associate professor of human genetics and Yue Feng, PhD, associate professor of pharmacology, with additional contributions from J. David Sweatt, PhD, chair of neurobiology at University of Alabama, Birmingham.

The research was supported by the National Institutes of Health.

Reference:

S.E. Lee et al. RGS14 is a natural suppressor of both synaptic plasticity in CA2 neurons and hippocampal-based learning and memory. PNAS Early Edition (2010). http://www.pnas.org/content/early/2010/09/03/1005362107.abstract

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Winship Cancer Institute of Emory University; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has a $2.5 billion budget, 17,600 employees, 2,500 full-time and 1,500 affiliated faculty, 4,700 students and trainees, and a $5.7 billion economic impact on metro Atlanta.

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu

More articles from Life Sciences:

nachricht Nerves control the body’s bacterial community
26.09.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Ageless ears? Elderly barn owls do not become hard of hearing
26.09.2017 | Carl von Ossietzky-Universität Oldenburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Nerves control the body’s bacterial community

26.09.2017 | Life Sciences

Four elements make 2-D optical platform

26.09.2017 | Physics and Astronomy

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>