Novel role of bHLH protein Daughterless in synaptogenesis

Basic Helix Loop Helix (bHLH)proteins are a class of highly conserved transcription factors. Proneural bHLH proteins have been extensively studied for their role in neurogenesisregulation, however the role of class 1 bHLH proteins in postmitotic cells remains unknown. Class 1 bHLH proteins function by heterodimerizing with class II or V bHLH proteins, orhomodimerizing to alter transcription. Ourlab has identified a novel role of the class 1 bHLH protein, Daughterless (Da),in postmitotic neurons in Drosophila Melanogaster, in which it restricts synaptogenesis. Here, we show that Da performs this function in part through restricting Neurexin expression, a cell adhesion protein. Our data also suggests that Da cooperates with the class V bHLH protein, Extramacrochaetae (Emc), in postmitotic neurons. Emc is a well‐established binding partner of Da during development, where it serves to sequester Da, preventing DNA binding. Taken together, these results provide a novel role for the class 1 bHLH protein, Daughterless, in postmitotic neurons.