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miRNAs and sexual behavior: a view from the female fly

27 Jun 19

Speaker: Daniel L. Garaulet, PhD. Research Associate, Memorial Sloan-Kettering Cancer Center, Sloan Kettering Institute, New York.  



Organizers: IRB Barcelona
Date: Thursday 27 June, 3.00pm
Place: Fèlix Serratosa Hall, Parc Cientific de Barcelona

Host: Marco Milán, PhD - IRB Barcelona, MOD's Programme


Whether to sleep when tired, drink when thirsty, or eat when hungry, reproductive and survival success depends on an animal’s capacity for dynamic coordination of internal states with appropriate behaviors. A classic example involves the radical reorganization of conducts that female insects undergo following mating. While mature virgins seek and allow copulation, they adapt their habits to produce, raise, and protect their progeny after mating. In Drosophila, the mechanisms underlying this post-mating switch have been studied intensively. However, the genetic determinants of virgin behavior remain elusive, leading to the assumption that virgin behavior represents the default female condition.
Here we identify a regulatory cascade of transcription factors that is essential to specify virgin behavior. This cascade is initiated by the post-transcriptional regulation of the homothorax (hth) gene by two BX-C miRNAs in abdominal neurons. Both deletion of BX-C miRNAs or its array of binding sites in the 3´UTR of hth, robustly promote mated behaviors in virgin females. Furthermore, this behavioral inversion is due to Hth-mediated downregulation of the doublesex (dsx) gene in specific lineages of neurons in mutants.
Overall, we uncover a surprising linear regulatory pathway localized to specific neurons that is crucial to prevent the constitutive induction of post-mated behaviors in virgin flies, constituting a key linkage of internal state to behavior.

Extraordinary Seminars of the Mechanisms of Disease Programme