Odors can alter gene expression in an olfactory neuron

A breakthrough technique that allows scientists to view individually-labeled tumor cells as they move about in real time in a live mouse may enable scientists to develop microenvironment-specific drugs against cancer, researchers report at the American Society for Cell Biology (ASCB) 48th Annual Meeting, Dec. 13-17, 2008 in San Francisco. With this technique, researchers at

Full Post: New technique to view labeled tumor cells in ‘real’ time

New research from University of California, Davis, shows why a species of tiny worm can learn to ignore an odor - information that could have implications for how human memories are formed.

Scientists have known for decades that sensory neurons - nerves in places like our fingers, ears and eyes - begin the complex task of processing sights, sounds and other stimuli before forwarding the job to the body’s mainframe computer: the brain. But just how these neurons accomplish their task has not been well understood.

Now researchers at UC Davis have made a startling discovery: that in olfactory neurons, odor bypasses the normal regulatory pathways in the nucleus and instead boosts synthesis of a protein by acting on RNA, the molecular messengers that typically carry instructions from DNA in the nucleus to protein-building mechanisms in the cell.

“What is unique about this study is that it provides the first evidence that a chemical in our environment changes gene expression in its own, very specific way within a sensory organ,” explained Noelle L’Etoile, the study’s principal investigator and assistant professor of psychiatry and behavioral sciences at UC Davis’s Center for Neuroscience. “This implicates the real importance of RNA in controlling when proteins are made, and shows that the environment can actually change what RNA does.”

Probing deep into the molecular pathways of a microscopic worm called C. elegans , L’Etoile and co-author Julia Kaye, a postdoctoral researcher at the center, found that prolonged exposure to an odor boosts production of a protein that curbs the worm’s response to the smell, and that this activity happens very close to the area where the smell enters the neuron. Their study appears in the January 15 issue of the journal Neuron .

The regulatory protein guiding this response is also found in an important region of memory formation in the mammalian brain, L’Etoile explained. “So this work could lead to discoveries about the role these proteins play in memory and higher order learning in humans,” she said.

To study the molecular basis of smell, the researchers used a population of C. elegans with a mutation that blocks the worms’ normal ability to ignore odors that are not linked to food. L’Etoile had earlier found that this mutation occurs in a region of RNA that regulates the expression, or synthesis, of a protein called PKG.

In the new study, they found that RNA in sensory neurons of the defective worms no longer binds to Pumilio proteins, regulatory molecules found in a diversity of species from yeast to humans. This led to their discovery that when normal worms are exposed to the odor of butanone with no food link, a Pumilio protein in the olfactory neuron ratchets up production of PKG, prompting the creatures to eventually lose interest in the smell. The discovery holds an additional, new twist, L’Etoile added: an exciting role reversal for Pumilio proteins, which until now have only been known to suppress protein synthesis.



New research provides valuable insight into the molecular mechanisms that allow experience to influence behavior. The study, published by Cell Press in the January 15th issue of the journal Neuron , shows that a normally repressive protein can promote plasticity in sensory neurons by linking odor stimulation with the synthesis of a key adaptation protein.

Full Post: Repressive protein plays unexpected role in odor adaptation

Humans and mice are attracted by the same odors. This has been revealed for the first time by a team of French researchers in the “Neurosciences sensorielles, comportement, cognition” Unit (CNRS / Université Lyon 1). Published on January 16, 2009 in the journal Plos One, their work confirms that olfactory preferences are not solely

Full Post: Mice and men express the same olfactory preferences

Rats whose mothers were fed alcohol during pregnancy are more attracted to the smell of liquor during puberty. Researchers writing in BioMed Central’s open access journal Behavioral and Brain Functions have shown that rats exposed during gestation find the smell of alcohol on another rat’s breath during adolescence more attractive than animals with no prior

Full Post: Important relationship between fetal and adolescent alcohol experiences

A new Rice University study published in the Journal of Neuroscience found that socioemotional meanings, including sexual ones, are conveyed in human sweat. Denise Chen, assistant professor of psychology at Rice, looked at how the brains of female volunteers processed and encoded the smell of sexual sweat from men. The results of the experiment indicated

Full Post: Understanding human smell at the neural level

Researchers at the University of Southern California (USC) have identified a novel mechanism in the regulation and differentiation of neural stem cells. Researchers found that the protein receptor Ryk has a key role in the differentiation of neural stem cells, and demonstrated a signaling mechanism that regulates neuronal differentiation as stem cells begin to grow

Full Post: Discovery of mechanism that regulates the development of stem cells into neurons