title: Complex and non-redundant signals from individual odor receptors that underlie chemotaxis behavior in Drosophila melanogaster larvae.
abstract: The rules by which odor receptors encode odors and allow behavior are still largely unexplored. Although large data sets of electrophysiological responses of receptors to odors have been generated, few hypotheses have been tested with behavioral assays. We use a data set on odor responses of Drosophila larval odor receptors coupled with chemotaxis behavioral assays to examine rules of odor coding. Using mutants of odor receptors, we have found that odor receptors with similar electrophysiological responses to odors across concentrations play non-redundant roles in odor coding at specific odor concentrations. We have also found that high affinity receptors for odors determine behavioral response thresholds, but the rules for determining peak behavioral responses are more complex. While receptor mutants typically show loss of attraction to odors, some receptor mutants result in increased attraction at specific odor concentrations. The odor receptor mutants were rescued using transgenic expression of odor receptors, validating assignment of phenotypes to the alleles. Vapor pressures alone cannot fully explain behavior in our assay. Finally, some odors that did not elicit strong electrophysiological responses are associated with behavioral phenotypes upon examination of odor receptor mutants. This result is consistent with the role of sensory neurons in lateral inhibition via local interneurons in the antennal lobe. Taken together, our results suggest a complexity of odor coding rules even in a simple olfactory sensory system.
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Jeewanjot S
authors.initials: JS
authors.lastname: Grewal
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Nguyen
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Raquel
authors.initials: R
authors.lastname: Robles
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Cho
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Karolina
authors.initials: K
authors.lastname: Kir
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Fledderman
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: George
authors.initials: G
authors.lastname: Gacharna
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Wesolowski
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Christie
authors.initials: C
authors.lastname: Klinger
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Pedro
authors.initials: P
authors.lastname: Vallejo
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Lorien
authors.initials: L
authors.lastname: Menhennett
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Abhiram
authors.initials: A
authors.lastname: Nagaraj
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Chineze
authors.initials: C
authors.lastname: Ebo
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Garrett
authors.initials: G
authors.lastname: Peacy
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Eftihia
authors.initials: E
authors.lastname: Davelis
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: David
authors.initials: D
authors.lastname: Kucher
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Giers
authors.affiliation: Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA skreher@dom.edu.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Kreher
keywords: Drosophila; Odor receptors; Olfaction; Or42a; Or42b