A key protein essential for odor and survival has been identified

summary: The Orco protein is essential for the survival of olfactory neurons in ants. Mutating the orco gene in the ants Harpegnathos saltator resulted in a significant reduction in the number of olfactory neurons, impairing their social interactions.

This study highlights the importance of Orco in neural development and social communication in ants. Understanding these mechanisms can provide insight into sensory-mediated social behavior in both animals and humans.

Key facts:

• The Orco protein is vital for the development and survival of olfactory neurons in ants.
• Mutant ants lacking Orco suffered significant neuronal death and impaired social interactions.
• The study provides new insights into how sensory systems and social behaviors in animals are linked.

source: New york university

While smell plays a big role in social interactions between humans — for example, signaling fear or generating closeness — for ants, it is extremely important.

Researchers from New York University and the University of Florida found that a key protein called Orco, which is essential for olfactory cell function, is also important for cell survival in ants.

Their study showed that mutated orco The gene is in Harpenathus salatator Jumping ants dramatically reduced the number of olfactory neurons, suggesting that Orco is essential for the development and life of these cells.

Results published in Advancement of scienceProvides insight into the cellular and molecular basis of how animals communicate socially.

“Understanding how the nervous system evolves is among the most pressing challenges in modern neuroscience,” said Bogdan Serebrennikov, a postdoctoral fellow in the Department of Biology at NYU and first author of the study.

Odor sensing and mutant ants

Ants have evolved nearly 400 odor receptors, a number closer to humans than most other insects, thanks to their use of pheromone communication.

“Ants, like humans, are highly social and exhibit cooperative social behavior, thus providing an ideal system for studying sensory social behavior,” explained Hua Yan, assistant professor of biology at the University of Florida and lead author of the study.

“Expanded odorant receptor genes allow ants to talk to each other in a large community of hundreds, thousands, or up to a million individuals.”

Even for humans, who rely on other senses to communicate, smell is essential.

“Loss of function of odorant receptor neurons leads to deficits in olfactory sensing and is often associated with social isolation, neurological disorders such as schizophrenia, and social disorders such as autism,” Yan added.

To better understand how ants’ sense of smell affects their social interactions, researchers from New York University previously created the first genetically modified ants using CRISPR to modify their sense of smell. orco The gene. These “mutated” ants, which lacked the Orco protein, had changes in their olfactory organs and had difficulty interacting.

“We found that the antennae – the ant’s ‘nose’ – contained very few cells. They were almost empty, indicating that the cells responsible for the sense of smell were absent in the mutant ants,” Yan said.

Neuronal survival depends on Orco

In their new study in Advancement of scienceThe researchers used single-nucleus gene expression profiling of ant antennae and fluorescence microscopy to analyze olfactory cell development. It turns out that mutant insects lacking Orco lose most of their olfactory neurons before adulthood.

“The cells seem to be established normally, and they begin to grow, change shape, and turn on certain genes that they will need later, such as odorant receptors,” says Serebrennikov.

“Once developing cells turn on odorant receptors, they quickly begin to die in massive quantities.”

This neurological death may be due to stress. Because the odorant receptors in the mutant ants cannot form a complex with Orco to travel to the cell membrane, the newly made receptors clog the organelles, leading to stress and death.

Such neuronal death may also exhibit patterns specific to social insects. “Until now, these unique processes have not been found in solitary insects, and may provide important evidence that neuroevolution has evolved to adapt to the expansion of odorant receptor genes,” said Kylie Sieber, a doctoral student at the University of Florida and the researcher. -First author of the study.

Interestingly, some odorant receptors survived even without Orco. The cells in which they were present also expressed other types of receptors, suggesting that the activity they facilitate is essential for neuronal development.

“Some neurons must ‘fire’ periodically to develop properly. Without Orco, the olfactory cells did not ‘fire’ and complete their development, leading to their death,” Serebrennikov said.

The researchers also found that some odor receptors are found in non-odour-related cells, such as mechanosensory neurons that detect movement and glia, which wrap around neurons and help them perform their functions.

This may be due to incomplete gene regulation, causing odorant receptors to be mistakenly activated by nearby genomic regions that normally regulate other genes in other cells. Alternatively, the receptors may have a new function in these cells, such as odorant receptors found in glial cells. C. elegans Worms or human sperm.

“Switching on odor receptor genes in cells that do not sense odor could be completely useless to the organism — but again, evolution tends to take advantage of such errors to give existing genes a new function, so perhaps there is an exciting new role for receptors,” Serebrennikov noted. Smell in non-smell cells, which we will discover in the future.

“Our findings advance our understanding of the sensory systems of social insects, including olfactory neural development that creates the framework for social communication,” Yan said.

Financing: Other authors of the study include Olena Columba, Jakub Mlejnic, and Shadi Jafari. This research was supported by the National Institutes of Health (R01-DC020203, T32-DC015994), the National Science Foundation Industry-University Cooperative Research Center for Arthropod Management Technologies (#IIP1821914), and the Human Frontier Sciences Program (LT000010/2020-). to).

About neuroscience and genetics research news

author: Rachel Harrison
source: New york university
communication: Rachel Harrison – New York University
picture: Image credited to Neuroscience News

Original search: Open access.
“Orco-dependent survival of odorant receptor neurons in ants“By Bogdan Serebrennikov et al. Advancement of science

a summary

Orco-dependent survival of odorant receptor neurons in ants

Olfaction is essential for complex social behavior in insects. To discriminate between complex social signals, ants have evolved a large number of organisms Smell receptors (or) Genes.

Mutations in the odorant receptor-binding gene orco It results in the loss of ~80% of the antennal lobe glomeruli in the jumping ant Harpenathus salatator. However, the cellular mechanism remains unclear.

Here, we show massive apoptosis of odorant receptor neurons (ORNs) at mid- and late stages of pupal development, possibly due to ER stress in the absence of Orco.

Further analysis of the bulk and single-core transcriptomes shows this, although it is more than that orco– Expression of ORNs dies orco Converts, a small percentage of whom survive: Arabized Ionotropic receptors (er) Genes that form IR complexes.

In addition, we found that some or The genes are expressed in mechanosensory neurons and non-neuronal cells, possibly due to leaky regulation from nearby non-neuronal cells.or Genes.

Our findings provide a comprehensive overview of ORN development or Expression in H. Salator.