HSP90, a capacitor of behavioral variation

Area of Science:

• Genetics
• Neuroscience
• Chronobiology

Background:

• Gene regulation significantly influences diverse behaviors, including aggression, courtship, sexual orientation, and sleep-wake cycles.
• While gene mutations alter behavior, the origins of substantial individual and lifetime behavioral variation remain largely unexplained.

Purpose of the Study:

• To investigate the role of Heat Shock Protein 90 (HSP90) in the circadian control of behavior in Drosophila.
• To determine if HSP90 modulates the translation of molecular circadian rhythms into behavioral output.

Main Methods:

• Utilized mutagenesis and pharmacological inhibition to reduce HSP90 function in Drosophila.
• Assessed the impact of altered HSP90 levels on the circadian clock's molecular oscillations.
• Quantified the coupling between molecular oscillations and behavioral activity patterns.

Main Results:

• Partial loss of HSP90 function did not disrupt the core circadian clock mechanism.
• HSP90 deficiency impaired the translation of molecular oscillations into consistent behavioral rhythms.
• HSP90-deficient flies exhibited significant variation in individual behavioral activity patterns, uncoupled from molecular rhythms.

Conclusions:

• HSP90 acts as a crucial capacitor of behavioral variation, similar to its known role in morphological variation.
• Decreased HSP90 activity leads to increased behavioral variability within a population and across an individual's lifespan.