Chromatin Affects the Sex Drive of Flies

The project that I am working on in the Volkan Lab fits neatly into one of the lab’s broader questions: how chromatin regulation around master genes affects behavior. In regards to the fruit flies I will be studying, the behavior in question is male courtship and the master gene I will be looking at is called Fruitless, or fru. This fru gene transcribes a transcription factor that has been found to be the primary effector in the development of appropriate courtship rituals in male flies.

My specific project is to try and find the mechanism through which peripheral sensory systems affect courtship behavior. The sensory system I will be studying is a particular receptor in the olfactory system called IR84a. This receptor is responsible for sensing (and be activated by) phenylacetic acid and phenylacetyl aldehyde, two chemicals that are found on the fruits and plants that the flies use as oviposition sites and food sources. Upon exposure to these chemicals, and thus activation of the receptors, male fruit flies experience increased courtship behavior. In addition, when mutants are made that lack the IR84a receptor, the male flies not only lose their ability to sense these aphrodisiacs but they also display a lowered base courtship rate compared to wild type male flies. These two phenotypes clearly demonstrate IR84a’s link to courtship.

Studying IR84a ties into the overall question of the lab because we hypothesize that the mechanism through which IR84a affects courtship behavior is by regulating the chromatin state around the master gene fruitless. A process called ChIP, Chromatin Immunoprecipitation, will be performed to assess the chromatin state around fruitless in both the peripheral and central nervous systems of both IR84a mutant and wild-type male flies. If there is a difference between the two chromatin states, then this will provide evidence in favor of our hypothesized mechanism.

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