The achaete-scute complex (AS-C) is a group of four genes (achaete, scute, lethal of scute, and asense) in the fruit fly Drosophila melanogaster. These genes encode basic helix-loop-helix transcription factors that have been best studied in their regulation of nervous system development. Because of their role in specifying neuroblast fate, the genes of the AS-C are called proneural genes. However, the AS-C has non-proneural functions, such as specifying muscle and gut progenitors. Homologues of AS-C in other animals, including humans and other vertebrates, have similar functions.
Genes of the AS-C interact with the Notch pathway in both their proneural functions as well as their specification of gut and muscle cells.