Michael Stadlmeier (Wuhr lab):"Capturing Proximity: Towards Sensitive Cross-Linking Mass Spectrometry."
To gain a better understanding about biology, it is in many cases crucial to elucidate protein structure or identify vast protein interaction networks. In this talk, I will demonstrate how we can utilize organic chemistry to fixate proximity in and between proteins, allowing us to employ mass-spectrometry for the analysis. In addition, I will show how we can overcome current limitations by using a novel cross-linking reagent, cliXlink, which allows for the enrichment of low-abundant cross-linked peptides. The resulting increase in sensitivity will enable the analysis of samples with higher complexity, making cross-linking mass spectrometry an invaluable tool to investigate cell biology.
Davide Deutsch (Murthy lab):"The Neural Basis for a Persistent Internal State in Drosophila Females."
Sustained changes in mood or action require persistent changes in neural activity, but it has been difficult to identify and characterize the neural circuit mechanisms that underlie persistent activity and contribute to long-lasting changes in behavior.
We activate a single class of neurons that express the sex determination transcription factor doublesex in the Drosophila melanogaster female brain using optogenetics. Following activation, females showed increased receptivity and aggression, as well as male-like behaviors. By reconstructing cells in a volume electron microscopic (EM) image of the female brain, and using genetic tools to target specific cell types, we were able to focus on a small number of cells termed ‘pC1-Alpha’ that are sufficient for driving the aggressive and male-like behaviors. Using calcium imaging, we located minutes-long persistent neural activity in the female central brain following pC1-Alpha activation, and by mapping all the synaptic partners of a pC1-Alpha neuron in the EM volume, we found that this cell is reciprocally connected with a specific set of sexually dimorphic neurons.
Our work thus links minutes-long persistent changes in behavior with persistent neural activity and recurrent circuit architecture in the female brain.